✨ feat(auth): implement OIDC client methods (ADR-0028 Phase B.3)

Implements the 4 OIDCClient methods that were TODO skeletons in PR #69:
- Discover(ctx) — fetch + cache .well-known/openid-configuration
- RefreshJWKS(ctx) — fetch JWKS, parse RSA public keys (n/e base64-url)
- ExchangeCode(ctx, code, codeVerifier, redirectURI) — POST token endpoint with PKCE
- ValidateIDToken(ctx, idToken) — verify signature via JWKS, validate claims

Plus 7 unit tests using httptest.NewServer to mock the OIDC provider:
TestDiscover_HappyPath, TestDiscover_Idempotent, TestRefreshJWKS_HappyPath,
TestExchangeCode_HappyPath, TestValidateIDToken_HappyPath,
TestValidateIDToken_RejectsExpired, TestValidateIDToken_RejectsWrongIssuer.

Mostly authored by Mistral Vibe (batch6, $3.51 / 46 steps), trainer-takeover
on 2 bugs:
- closure auto-reference bug (server := httptest.NewServer with closure
  body referencing server.URL — needs var server *httptest.Server then
  server = ...)
- ExchangeCode body wasn't being sent (req.PostForm = form is wrong;
  must pass strings.NewReader(form.Encode()) as the request body)

CHANGELOG.md

@@ -0,0 +1,25 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- ✨ `GET /api/v1/uptime` endpoint (PR #67) — returns server start_time and uptime_seconds
+- 📝 mkcert local HTTPS doc + Makefile `cert` target (PR #68) — prep for ADR-0028 Phase B OIDC callbacks
+- ✨ `pkg/auth/` skeleton for OpenID Connect (PR #69) — types + client surface, handlers come later (Phase B.3+)
+- 📝 ADR-0028 Phase B roadmap document (PR #71) — outlines remaining B.3 / B.4 / B.5 work
+
+## [0.1.0] - 2026-05-05
+
+### Added
+
+- Magic-link passwordless authentication (ADR-0028 Phases A.1 through A.5, PRs #59-#63)
+- OIDC provider config skeleton (ADR-0028 Phase B.1 prep, PR #64)
+- Magic-link expired-token cleanup loop (PR #65)
+- Mailpit local SMTP infrastructure (ADR-0029)
+- BDD parallel email assertion strategy (ADR-0030)

Makefile

@@ -0,0 +1,24 @@
+# dance-lessons-coach Makefile — minimal targets for local development.
+# This is a starter Makefile ; expand as needed (build, test, run, etc.).
+# Existing build/test workflows live in scripts/ and remain authoritative.
+
+CERT_DIR := ./certs
+
+.PHONY: help cert clean-cert
+
+help:
+	@echo "Available targets:"
+	@echo "  cert        Generate local-dev TLS certs via mkcert (cf. documentation/MKCERT.md)"
+	@echo "  clean-cert  Remove generated TLS certs"
+	@echo "  help        Show this help"
+
+cert: $(CERT_DIR)
+	@command -v mkcert >/dev/null 2>&1 || { echo >&2 "mkcert not found. See documentation/MKCERT.md to install."; exit 1; }
+	mkcert -cert-file $(CERT_DIR)/dev-cert.pem -key-file $(CERT_DIR)/dev-key.pem localhost 127.0.0.1 ::1
+	@echo "Certs ready at $(CERT_DIR)/. Cf. documentation/MKCERT.md for usage."
+
+$(CERT_DIR):
+	mkdir -p $(CERT_DIR)
+
+clean-cert:
+	rm -rf $(CERT_DIR)

adr/0028-passwordless-auth-migration.md

@@ -0,0 +1,147 @@
+# 28. Passwordless authentication: magic link → OpenID Connect
+
+**Date:** 2026-05-05
+**Status:** Proposed
+**Authors:** Gabriel Radureau, AI Agent
+
+## Context and Problem Statement
+
+ADR-0018 (now Implemented) shipped a username + password authentication system with bcrypt hashing, JWT tokens, admin master password, and admin-assisted password reset. It works, but it carries the cost-of-passwords : we store password hashes, support password reset flows, and maintain a credential-rotation policy. Users hate passwords ; ops and security pay for them.
+
+Two industry-standard alternatives exist :
+1. **Magic link by email** — user enters their email, receives a one-time token in a clickable link, link consumes the token and issues a session JWT. No password stored.
+2. **OpenID Connect Authorization Code flow** — delegate authentication to an external Identity Provider (e.g. Authelia, Keycloak, Auth0, Google) ; our app receives an `id_token` after the OIDC dance.
+
+We want to **migrate to passwordless** for new sign-ups while keeping the existing username/password code path operational during the transition (no flag-day breakage). The two passwordless mechanisms above complement each other : magic link is simpler for first-party users on day 1 ; OIDC is the right answer for second-party users (other ARCODANGE products, partner integrations) and for admin SSO.
+
+A third constraint : ARCODANGE local development must use HTTPS for OAuth callbacks to be valid (most OIDC providers reject `http://localhost` redirect URIs in their default config). `mkcert` is the canonical local-CA tool for this.
+
+## Decision Drivers
+
+* **Reduce password-related attack surface** — no hash storage, no breach-and-reuse risk, no password reset abuse vectors
+* **User experience** — passwordless is faster for the user (1 click in email vs typing/remembering password)
+* **Operational simplicity** — no password reset flow to maintain ; the password-reset code can be removed once migration is complete
+* **Multi-product readiness** — OIDC is the prerequisite for cross-product SSO across the ARCODANGE portfolio
+* **Backwards compatibility** — must not break existing tokens or BDD scenarios mid-migration
+* **Local dev parity** — HTTPS in dev so OAuth flows can be tested locally without provider-specific workarounds
+
+## Considered Options
+
+### Option 1 (Chosen): Sequenced — magic link first, OIDC second
+
+Deliver in two phases :
+
+* **Phase A — Magic link**
+  - Add `POST /api/v1/auth/magic-link/request` (body: `{email}`) — generates token, stores it (TTL ~15 min), sends email via SMTP
+  - Add `GET /api/v1/auth/magic-link/consume?token=<...>` — single-use consumption, issues a JWT, returns it as cookie + JSON body
+  - Reuse the existing JWT issuance + secret retention infrastructure (ADR-0021)
+  - Existing `/api/v1/auth/login` (username/password) stays operational during transition
+
+* **Phase B — OpenID Connect Authorization Code with PKCE**
+  - Add `GET /api/v1/auth/oidc/start` — generates state + PKCE verifier, redirects to provider's `authorization_endpoint`
+  - Add `GET /api/v1/auth/oidc/callback` — exchanges code for tokens, validates `id_token` signature against provider's JWKS, issues internal JWT
+  - Provider URL configurable per environment (`auth.oidc.issuer_url`, `auth.oidc.client_id`, `auth.oidc.client_secret`)
+  - Allow multiple providers in config (key by provider name, e.g. `arcodange-sso`)
+  - Local dev requires HTTPS — `mkcert` setup documented in `documentation/DEV_SETUP.md`
+
+* **Phase C (later, separate ADR) — Decommission password auth**
+  - Once all users have migrated, remove the password endpoints, remove the password_hash column, mark ADR-0018 as Superseded by this ADR
+
+### Option 2: All-at-once OIDC, no magic link
+
+Skip magic link, jump straight to OIDC.
+
+* Good — single migration, no intermediate state
+* Bad — requires an OIDC provider operational on day 1, which we don't have configured
+* Bad — magic link has zero infra dependencies (just SMTP) ; OIDC requires running an IdP or paying for one
+
+### Option 3: Magic link only, no OIDC
+
+Stop at Phase A.
+
+* Good — simplest implementation
+* Bad — doesn't solve cross-product SSO ; we'd re-do this work later for the broader ARCODANGE portfolio
+
+### Option 4: Status quo (do nothing)
+
+Keep username + password.
+
+* Good — zero effort
+* Bad — passwords stay forever ; ARCODANGE locks itself out of integration scenarios that expect OIDC
+
+## Decision Outcome
+
+Chosen option : **Option 1, sequenced magic link → OIDC**.
+
+Rationale :
+- Magic link is implementable today with zero infra dependencies beyond the email infrastructure (ADR-0029)
+- OIDC requires running an IdP locally (Authelia or Keycloak) — that's another container in the dev stack and another ADR's worth of decision work, but the magic-link work is the natural prerequisite (token-by-email plumbing is reused)
+- Sequenced delivery means we never have to roll back : Phase A works alone, Phase B layers on top, Phase C cleans up
+
+## Implementation Plan
+
+### Phase A — Magic link (target: 2-3 PRs)
+
+1. **A.1 — Storage** : add a `magic_link_tokens` table (id, email, token_hash, expires_at, consumed_at). Repository pattern alongside `pkg/user/postgres_repository.go`.
+2. **A.2 — Token endpoint** : `POST /api/v1/auth/magic-link/request` generates a token, stores it (hashed), enqueues an email send. Rate-limited (cf. ADR-0022) by email address.
+3. **A.3 — Consume endpoint** : `GET /api/v1/auth/magic-link/consume?token=...` validates + marks consumed + issues JWT. Returns `Set-Cookie` and `{token: jwt}` body.
+4. **A.4 — Sign-up via magic link** : if the email is unknown, the consume endpoint creates the user record. (No separate "sign-up" flow needed — first magic link IS the sign-up.)
+5. **A.5 — BDD coverage** : scenarios for happy path, expired token, double-consume, wrong-email, rate-limit. Cf. ADR-0030 for the email assertion strategy.
+
+### Phase B — OIDC Code flow with PKCE (target: 3-4 PRs)
+
+1. **B.1 — Local IdP** : choose Authelia or Keycloak for local development. Add to `docker-compose.yml` with default test configuration.
+2. **B.2 — mkcert** : document local HTTPS setup in `documentation/DEV_SETUP.md`, add `make cert` target.
+3. **B.3 — OIDC client** : `pkg/auth/oidc.go` — discovery, JWKS cache, code exchange with PKCE.
+4. **B.4 — Endpoints** : `/oidc/start` and `/oidc/callback`.
+5. **B.5 — Provider config** : `auth.oidc.providers` map in config (cf. ADR-0006 Viper) ; multi-provider supported.
+6. **B.6 — BDD coverage** : end-to-end scenarios using a mock OIDC server (or the local Authelia instance with deterministic users).
+
+### Phase C — Decommission password (separate ADR after A+B in production)
+
+Out of scope for this ADR. Will be ADR-NNNN when migration is complete.
+
+## Pros and Cons of the Options
+
+### Option 1 (Chosen — Sequenced)
+
+* Good — incremental, no flag day, each phase shippable on its own
+* Good — reuses existing JWT infrastructure (ADR-0021 secret retention)
+* Good — magic link work is a prerequisite for OIDC anyway (email plumbing, mkcert)
+* Bad — total work spans 2 sprints, longer time-to-OIDC than Option 2
+* Mitigation: after Phase A, the team can stop if priorities shift — magic link alone is a complete improvement
+
+### Option 2 (All OIDC)
+
+* Good — single migration
+* Bad — requires IdP operational from day 1
+* Bad — local dev environment more complex than necessary for the magic link case
+
+### Option 3 (Magic link only)
+
+* Good — minimal scope
+* Bad — re-work later for SSO
+
+### Option 4 (Status quo)
+
+* Good — zero effort
+* Bad — accumulating tech debt
+
+## Consequences
+
+* `pkg/auth/` package created (currently auth code lives in `pkg/user/`) — separation is now justified by the multi-mechanism scope
+* `pkg/user/api/auth_handler.go` continues to serve username/password during transition (Phase A and B), removed in Phase C
+* `documentation/DEV_SETUP.md` becomes a load-bearing doc for new contributors (mkcert + docker-compose with mailpit + Authelia)
+* The 4 new endpoints (`magic-link/request`, `magic-link/consume`, `oidc/start`, `oidc/callback`) require their own ADR entries in the API doc + Swagger annotations
+* Phase A's magic link plumbing depends on **ADR-0029** (email infrastructure decision) — that ADR ships first
+* BDD scenarios for Phase A depend on **ADR-0030** (email testing strategy with parallel BDD) — that ADR ships before any Phase A scenario lands
+
+## Links
+
+* Email infrastructure : [ADR-0029](0029-email-infrastructure-mailpit.md)
+* BDD email testing strategy : [ADR-0030](0030-bdd-email-parallel-strategy.md)
+* Existing user auth (to be partially superseded by Phase C) : [ADR-0018](0018-user-management-auth-system.md)
+* JWT secret retention reused : [ADR-0021](0021-jwt-secret-retention-policy.md)
+* Rate limiting reused : [ADR-0022](0022-rate-limiting-cache-strategy.md)
+* OAuth 2.0 Authorization Code with PKCE : [RFC 7636](https://datatracker.ietf.org/doc/html/rfc7636)
+* OpenID Connect Core : [OpenID Foundation](https://openid.net/specs/openid-connect-core-1_0.html)

adr/0029-email-infrastructure-mailpit.md

@@ -0,0 +1,142 @@
+# 29. Email infrastructure: Mailpit local + production deferred
+
+**Date:** 2026-05-05
+**Status:** Proposed
+**Authors:** Gabriel Radureau, AI Agent
+
+## Context and Problem Statement
+
+ADR-0028 (passwordless auth) requires the application to send emails — magic-link tokens specifically. Email is a substrate decision : the choice of SMTP provider, the abstraction in code, and the local development experience all depend on it.
+
+Two separate concerns :
+
+1. **Local development + BDD tests** : we need a local SMTP receiver that captures emails and exposes them for inspection. Real email providers (Gmail, SES, SendGrid) are unsuitable for local dev — they cost money, leak test data, and rate-limit aggressively.
+2. **Production** : the application needs to actually deliver mail to user inboxes. This decision is deferred — see "Out of scope" below.
+
+ARCODANGE already has the **Mailpit** docker image pulled locally (`axllent/mailpit:latest`, 51 MB). Mailpit captures SMTP submissions on a port, stores them in-memory, exposes them via HTTP UI (default :8025) and an HTTP API (`/api/v1/messages`). It's the de-facto choice for Go projects needing local SMTP capture.
+
+The application code needs to be **provider-agnostic** : a `pkg/email` package with a `Sender` interface, a Mailpit-compatible SMTP implementation, and a contract that production can swap for a real provider's adapter without changing call sites.
+
+## Decision Drivers
+
+* **Local dev and CI must work without internet** — emails should never leave the docker network in tests
+* **Test inspection must be programmatic** — BDD tests assert on email content, not just "an email was sent"
+* **Production decision deferred** — we don't know the volume / SLA / compliance requirements yet ; over-committing now is premature
+* **Provider portability** — `pkg/email` interface lets us swap implementations without touching auth code
+* **Cost** — Mailpit is free, runs in a container, no API quota concerns
+
+## Considered Options
+
+### Option 1 (Chosen): Mailpit for local + tests, production via a production-grade provider TBD
+
+* Add Mailpit to `docker-compose.yml` (SMTP :1025, HTTP API :8025)
+* `pkg/email` package with a `Sender` interface
+* Default implementation : `SMTPSender` configured against the local Mailpit in dev/CI
+* Tests query Mailpit's HTTP API to inspect captured messages
+* Production deployment will add a separate `pkg/email/<provider>_sender.go` implementing the same interface — that decision is its own ADR
+
+### Option 2: MailHog instead of Mailpit
+
+MailHog is the older, well-known alternative. Mailpit is its modern successor, written in Go, with a richer API and active maintenance.
+
+* Bad — abandoned upstream (last commit 2020). Mailpit is the natural replacement.
+
+### Option 3: In-process mock email sender
+
+Write a `MockSender` that captures emails in a Go slice. No SMTP at all.
+
+* Good — fastest tests, zero infra
+* Bad — doesn't validate the actual SMTP wire format, the From/To/Subject headers, the encoding of multi-byte content, or the DKIM/Reply-To setup
+* Bad — doesn't double as a manual-inspection tool for the developer (no UI to look at the email)
+
+### Option 4: Send to a real but throwaway provider (Mailtrap, Mailosaur)
+
+External services that capture-and-display emails.
+
+* Good — production-similar paths
+* Bad — costs money, requires an account, leaks test data, doesn't work offline
+
+## Decision Outcome
+
+Chosen option : **Option 1 — Mailpit for local + tests, production deferred**.
+
+Rationale :
+- Mailpit is the modern, maintained successor to MailHog ; image is already on the dev machine
+- The interface-first design (`pkg/email.Sender`) means production swap is a future ADR, not a refactor
+- BDD tests have a real wire-format path to assert on (cf. ADR-0030)
+- Zero monthly cost in dev/CI
+
+## Implementation Plan
+
+1. **`pkg/email/sender.go`** — define the `Sender` interface :
+   ```go
+   type Sender interface {
+       Send(ctx context.Context, msg Message) error
+   }
+   type Message struct {
+       To      string
+       From    string
+       Subject string
+       BodyText string
+       BodyHTML string
+       Headers  map[string]string // for trace correlation, e.g. X-Test-Scenario-ID
+   }
+   ```
+2. **`pkg/email/smtp_sender.go`** — implementation using `net/smtp` (stdlib) configured by `auth.email.smtp_host`, `smtp_port`, `smtp_username`, `smtp_password`, `smtp_use_tls`. For Mailpit defaults : `smtp_host=localhost smtp_port=1025 smtp_use_tls=false`.
+3. **`pkg/email/sender_test.go`** — unit tests using `httptest`-style fake SMTP, plus a `*_integration_test.go` (build tag `integration`) hitting the live Mailpit.
+4. **`docker-compose.yml`** — add the `mailpit` service :
+   ```yaml
+   mailpit:
+     image: axllent/mailpit:latest
+     ports:
+       - "1025:1025"  # SMTP
+       - "8025:8025"  # HTTP UI / API
+     environment:
+       MP_MAX_MESSAGES: 5000
+   ```
+5. **`pkg/config/config.go`** — add the `auth.email.*` config keys with defaults pointing at local Mailpit.
+6. **Documentation** : `documentation/EMAIL.md` covering local setup, message inspection via UI (http://localhost:8025), API queries.
+
+## Pros and Cons of the Options
+
+### Option 1 (Chosen — Mailpit)
+
+* Good — already locally available, free, modern, maintained
+* Good — provider-agnostic interface decouples from prod choice
+* Good — full SMTP wire format = realistic test path
+* Good — UI for manual inspection during dev
+* Bad — requires Mailpit running (one more docker-compose service)
+* Bad — production decision still pending
+
+### Option 2 (MailHog)
+
+* Bad — unmaintained, choosing it would create immediate tech debt
+
+### Option 3 (Mock only)
+
+* Bad — too much abstraction loss, can't catch wire-level bugs
+
+### Option 4 (Mailtrap / Mailosaur)
+
+* Bad — cost, network dependency, account management
+
+## Consequences
+
+* New service in `docker-compose.yml` — developers run `docker compose up -d` once and Mailpit is on
+* New `pkg/email` package — auth code (ADR-0028 magic link) calls `Sender.Send()` rather than direct SMTP
+* New `auth.email.*` config keys, new env vars (`DLC_AUTH_EMAIL_SMTP_HOST` etc.)
+* Mailpit's HTTP API becomes part of the BDD test contract — tests use it to assert messages were sent (cf. ADR-0030)
+* Production sender ADR (TBD) will be a separate decision — this ADR explicitly does NOT pick a vendor for prod
+
+## Out of scope
+
+* **Production email provider selection** — separate ADR when we know volume / SLA / compliance constraints. Likely candidates: AWS SES, Postmark, SendGrid, Mailjet. Magic-link emails are transactional + low-volume — most providers handle that easily.
+* **DKIM/SPF/DMARC setup** — production deliverability concern, not a local-dev concern
+* **HTML email templating** — we'll start with plain-text emails ; HTML can be added with a template package (e.g. `html/template`) when ARCODANGE branding requires it
+
+## Links
+
+* Auth migration that requires this : [ADR-0028](0028-passwordless-auth-migration.md)
+* BDD test strategy that consumes Mailpit : [ADR-0030](0030-bdd-email-parallel-strategy.md)
+* Mailpit homepage : https://mailpit.axllent.org/
+* Mailpit API reference : https://mailpit.axllent.org/docs/api-v1/

adr/0030-bdd-email-parallel-strategy.md

@@ -0,0 +1,187 @@
+# 30. BDD email assertions with parallel test execution
+
+**Date:** 2026-05-05
+**Status:** Proposed
+**Authors:** Gabriel Radureau, AI Agent
+
+## Context and Problem Statement
+
+ADR-0028 introduces magic-link auth, which requires the application to send emails. ADR-0029 chose **Mailpit** as the local SMTP receiver for dev and BDD tests. The remaining decision : **how do BDD scenarios assert on the email content while running in parallel ?**
+
+Today (since [PR #35](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/35)), the BDD suite runs in parallel via per-package PostgreSQL schema isolation (cf. [ADR-0025](0025-bdd-scenario-isolation-strategies.md)). Each Go test package has its own schema ; tests inside a package run serially within that schema. This works because Postgres has named schemas with strong isolation. **Mailpit has no equivalent** — there is one inbox per Mailpit instance, shared across all senders.
+
+A naive integration would have parallel scenarios fight over each other's emails :
+- Scenario A : "request magic link for `test@example.com`" → email arrives
+- Scenario B (in parallel) : "request magic link for `test@example.com`" → email arrives
+- Both scenarios query Mailpit for `test@example.com` — they see each other's messages, assertions become flaky.
+
+We need a way to scope each scenario's emails so it only sees its own messages.
+
+## Decision Drivers
+
+* **No regression on parallelism** — BDD-isolation Phase 3 (PR #35) achieved a 2.85x speedup ; the email-assertion solution must not undo that
+* **No new container per test** — running one Mailpit per scenario would defeat the simplicity that made us choose Mailpit
+* **Determinism** — a scenario's email assertions must succeed regardless of how many other scenarios are running
+* **Realistic SMTP path** — we still want the full SMTP wire format exercised (cf. ADR-0029) ; we don't want to bypass Mailpit
+* **Cleanup hygiene** — old messages from previous test runs must not leak into a new run
+
+## Considered Options
+
+### Option 1 (Chosen): Per-test recipient scoping with deterministic addresses
+
+Each BDD scenario generates a unique email address for its test user, derived from the scenario key + a random suffix. Examples :
+
+- Scenario `magic-link-happy-path` → `magic-link-happy-path-<8hex>@bdd.local`
+- Scenario `magic-link-expired-token` → `magic-link-expired-token-<8hex>@bdd.local`
+
+The application code accepts any email format. The BDD scenario asserts on Mailpit's HTTP API filtering by the `to` address. Two parallel scenarios with different addresses can NEVER see each other's emails.
+
+**Cleanup** : at the start of each scenario, the BDD framework calls `DELETE /api/v1/search?query=to:<scenario-address>` on Mailpit to purge any leftover messages from prior runs.
+
+### Option 2: One Mailpit instance per Go test package
+
+Spawn a fresh Mailpit container in `TestMain` of each `features/<area>/` package. Each gets its own port range.
+
+* Good — strong isolation
+* Bad — heavyweight (one container per package = 5+ containers running)
+* Bad — port allocation complexity (similar to existing `pkg/bdd/parallel/port_manager.go`, but applied to Mailpit)
+* Bad — slow startup (Mailpit boot is ~200ms but adds up)
+
+### Option 3: One Mailpit instance, scenario-scoped via custom SMTP header
+
+Add a custom header `X-BDD-Scenario-ID: <key>` to outgoing emails. Tests query Mailpit filtered on that header.
+
+* Good — same single Mailpit
+* Bad — requires the application code to know the scenario ID at email-send time, which means a test-only path in production code
+* Bad — header propagation is fragile (gets stripped by some SMTP relays — not Mailpit, but real production providers might) ; we don't want a different code path between dev and prod
+
+### Option 4: Sequence parallel scenarios via per-scenario Mailpit lock
+
+Use a mutex / queue so no two scenarios that send email run concurrently.
+
+* Good — minimal code change
+* Bad — gives up the parallel speedup for any feature that involves email — that's most auth-related features going forward
+
+## Decision Outcome
+
+Chosen option : **Option 1 — per-test recipient scoping**.
+
+Rationale :
+- Recipient scoping is the simplest abstraction : the address IS the identity ; Mailpit's HTTP API natively supports filtering by recipient
+- Application code stays clean : it just sends to whatever address it's given. No test-mode branching.
+- Parallel-safe by construction : two scenarios cannot collide if they don't share an address
+- Cheap to implement : a few helper functions in `pkg/bdd/steps/email_steps.go` and a `mailpit.Client` package wrapping the HTTP API
+- Cleanup is per-scenario, not global — no "delete all messages" race between scenarios
+
+## Implementation Plan
+
+### Helper package : `pkg/bdd/mailpit/client.go`
+
+```go
+type Client struct {
+    BaseURL string  // default: http://localhost:8025
+    HTTP    *http.Client
+}
+
+// AwaitMessageTo polls Mailpit's HTTP API for a message addressed
+// to the given recipient, with a deadline. Returns the most recent
+// matching message or an error on timeout.
+func (c *Client) AwaitMessageTo(ctx context.Context, to string, timeout time.Duration) (*Message, error)
+
+// PurgeMessagesTo removes all messages addressed to the given
+// recipient. Idempotent and parallel-safe.
+func (c *Client) PurgeMessagesTo(ctx context.Context, to string) error
+
+type Message struct {
+    ID       string
+    From     string
+    To       []string
+    Subject  string
+    Text     string
+    HTML     string
+    Headers  map[string][]string
+}
+```
+
+### Helper steps : `pkg/bdd/steps/email_steps.go`
+
+```go
+func (s *EmailSteps) iHaveAnEmailAddressForThisScenario() error
+// Generates `<scenario-key>-<8hex>@bdd.local`, stores it in the scenario state.
+
+func (s *EmailSteps) iShouldReceiveAnEmailWithSubject(subject string) error
+// Polls AwaitMessageTo on the scenario's address, asserts subject equality.
+
+func (s *EmailSteps) theEmailShouldContain(snippet string) error
+// Re-fetches the most recent message and checks for substring in body.
+
+func (s *EmailSteps) theEmailContainsAMagicLinkToken() (string, error)
+// Extracts the token from the magic-link URL via regex, returns it.
+```
+
+### Scenario lifecycle
+
+- **Before each scenario** : `iHaveAnEmailAddressForThisScenario` is called (either explicitly via Background, or implicitly via a hook). The unique address is stored in the scenario's state. PurgeMessagesTo is called to clear any leftovers from prior runs of the same address (defensive — should be impossible since the suffix is random, but cheap).
+- **During the scenario** : the application sends to that address. Tests query for it.
+- **After each scenario** : no global cleanup needed — addresses are per-scenario unique, so they don't accumulate beyond Mailpit's `MP_MAX_MESSAGES=5000` cap.
+
+### Race-free deletion
+
+Mailpit's `DELETE /api/v1/search?query=to:<addr>` is atomic per recipient. Two concurrent scenarios with different addresses cannot interfere.
+
+### Sample scenario (auth-magic-link.feature)
+
+```gherkin
+@critical @magic-link
+Scenario: User receives a magic link by email
+  Given I have an email address for this scenario
+  When I request a magic link for my email address
+  Then I should receive an email with subject "Your magic link"
+  And the email contains a magic link token
+  When I consume the magic link token
+  Then I should receive a JWT
+```
+
+## Pros and Cons of the Options
+
+### Option 1 (Chosen)
+
+* Good — parallel-safe by construction
+* Good — application code unchanged ; test-only logic stays in the BDD layer
+* Good — Mailpit API supports the filter natively
+* Good — cleanup is fine-grained, no race
+* Bad — requires cooperative scenarios (each must request a unique address)
+* Mitigation : Background steps in feature files make it automatic
+
+### Option 2 (Mailpit per package)
+
+* Bad — operational complexity not justified for the test-only concern
+
+### Option 3 (Custom header scoping)
+
+* Bad — production code dirtied by test concerns
+
+### Option 4 (Lock-and-sequence)
+
+* Bad — gives up parallelism (the whole point of PR #35 + ADR-0025)
+
+## Consequences
+
+* `pkg/bdd/mailpit/` package is created with HTTP client + helper types
+* `pkg/bdd/steps/email_steps.go` package is created and registered in `steps.go`
+* `features/auth/` and any other email-using features have new BDD steps available
+* The local development docker-compose must run Mailpit before BDD tests run — to be added to the BDD test runner script `scripts/run-bdd-tests.sh`
+* Mailpit message TTL is governed by `MP_MAX_MESSAGES` (5000) — at parallel BDD volumes, that's enough headroom for ~50 scenarios × 100 messages each before any pruning kicks in
+
+## Out of scope
+
+* **Visual regression on email rendering** — text body assertions only ; HTML rendering checks belong in a separate Storybook-style harness
+* **Attachment handling** — magic-link emails are text-only ; ADRs for attachments will come if/when needed
+* **Email volume / rate-limit testing** — that's a load-test concern, not a BDD concern
+
+## Links
+
+* Auth migration depending on this : [ADR-0028](0028-passwordless-auth-migration.md)
+* Email infrastructure choice : [ADR-0029](0029-email-infrastructure-mailpit.md)
+* BDD parallelism foundation : [ADR-0025](0025-bdd-scenario-isolation-strategies.md), [PR #35](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/35)
+* Mailpit API : https://mailpit.axllent.org/docs/api-v1/

adr/README.md

@@ -31,6 +31,9 @@ This directory contains the Architecture Decision Records (ADRs) for the dance-l
 | [0025](0025-bdd-scenario-isolation-strategies.md) | BDD Scenario Isolation Strategies | Implemented |
 | [0026](0026-composite-info-endpoint.md) | Composite Info Endpoint vs Separate Calls | Implemented |
 | [0027](0027-ollama-tier1-onboarding.md) | Ollama Tier 1 onboarding via meta-trainer-bootstrap | Proposed |
+| [0028](0028-passwordless-auth-migration.md) | Passwordless authentication: magic link → OpenID Connect | Proposed |
+| [0029](0029-email-infrastructure-mailpit.md) | Email infrastructure: Mailpit local + production deferred | Proposed |
+| [0030](0030-bdd-email-parallel-strategy.md) | BDD email assertions with parallel test execution | Proposed |
 
 > **Note** : numbers `0011` and `0014` are not currently in use. Reserved for future ADRs or representing previously deleted entries.
 

docker-compose.yml

@@ -19,6 +19,23 @@ services:
       - dance-lessons-coach-network
     restart: unless-stopped
 
+  # Mailpit — local SMTP capture for dev + BDD parallel email tests.
+  # Cf. ADR-0029 (email infrastructure) and ADR-0030 (BDD parallel strategy).
+  # SMTP submission on :1025 (used by the app), HTTP UI + API on :8025
+  # (used by tests + manual inspection at http://localhost:8025).
+  mailpit:
+    image: axllent/mailpit:latest
+    container_name: dance-lessons-coach-mailpit
+    ports:
+      - "1025:1025"  # SMTP submission
+      - "8025:8025"  # HTTP UI / API
+    environment:
+      MP_MAX_MESSAGES: 5000
+      MP_SMTP_AUTH_ALLOW_INSECURE: 1  # local dev only - no TLS, no real auth
+    networks:
+      - dance-lessons-coach-network
+    restart: unless-stopped
+
   # Application service (for reference)
   # app:
   #   build: .

documentation/EMAIL.md

@@ -0,0 +1,107 @@
+# Email infrastructure
+
+Outgoing email transport. Per [ADR-0029](../adr/0029-email-infrastructure-mailpit.md): Mailpit for local dev + BDD tests, production sender deferred.
+
+## Local setup (one-time)
+
+Mailpit is part of `docker-compose.yml`:
+
+```bash
+docker compose up -d                 # starts postgres + mailpit
+docker compose ps                    # confirm both running
+```
+
+Mailpit listens on:
+- **SMTP submission** — `localhost:1025` (the app sends here)
+- **HTTP UI / API** — http://localhost:8025 (you inspect captured messages here)
+
+No real emails leave the docker network. No internet required.
+
+## Application configuration
+
+The application's outgoing transport is configured under `auth.email.*` in `config.yaml` (or via `DLC_AUTH_EMAIL_*` env vars). Defaults already match local Mailpit:
+
+```yaml
+auth:
+  email:
+    from: noreply@dance-lessons-coach.local
+    smtp_host: localhost
+    smtp_port: 1025
+    smtp_use_tls: false
+    timeout: 10s
+    # smtp_username + smtp_password left empty for local Mailpit
+```
+
+For production, override these to point at the chosen provider (SES, Postmark, etc.).
+
+## Inspecting messages
+
+### Web UI
+
+http://localhost:8025 — list of all captured messages, search, raw view, HTML preview.
+
+### HTTP API (for automation)
+
+```bash
+# Latest 10 messages (no filter — /api/v1/messages is for pagination)
+curl -s 'http://localhost:8025/api/v1/messages?limit=10' | jq
+
+# Messages for a specific recipient — use /api/v1/search, NOT /messages
+# (the latter's `query` param is for pagination only, not filtering ;
+# verified empirically 2026-05-05)
+curl -s 'http://localhost:8025/api/v1/search?query=to:test-user@bdd.local' | jq
+
+# Get a specific message by ID (full content, headers, attachments)
+curl -s 'http://localhost:8025/api/v1/message/<id>' | jq
+
+# Purge messages for a recipient (used in test cleanup) — also via /search
+curl -X DELETE 'http://localhost:8025/api/v1/search?query=to:test-user@bdd.local'
+```
+
+Full API: https://mailpit.axllent.org/docs/api-v1/
+
+## Sending email from Go code
+
+```go
+import "dance-lessons-coach/pkg/email"
+
+sender := email.NewSMTPSender(email.SMTPConfig{
+    Host: cfg.GetEmailConfig().SMTPHost,
+    Port: cfg.GetEmailConfig().SMTPPort,
+    // username/password optional — empty means no AUTH (Mailpit local)
+})
+
+err := sender.Send(ctx, email.Message{
+    To:       "alice@example.com",
+    From:     cfg.GetEmailConfig().From,
+    Subject:  "Your magic link",
+    BodyText: "Click: https://example.com/magic-link/consume?token=...",
+    Headers: map[string]string{
+        // optional — useful for BDD test correlation
+        "X-Trace-Id": "req-abc-123",
+    },
+})
+```
+
+Or, when both text and HTML are needed (`multipart/alternative`):
+
+```go
+err := sender.Send(ctx, email.Message{
+    To: "alice@example.com", From: "...", Subject: "...",
+    BodyText: "Click: https://...",
+    BodyHTML: `<p>Click <a href="https://...">your magic link</a></p>`,
+})
+```
+
+## Production sender (TBD)
+
+Not chosen yet. When ready, implement another `email.Sender` in
+`pkg/email/<provider>_sender.go` and wire it via the config. The
+`Sender` interface is the swap point — call sites don't change.
+
+## Cross-references
+
+- [ADR-0028 — Passwordless auth migration](../adr/0028-passwordless-auth-migration.md) (consumes this infrastructure)
+- [ADR-0029 — Email infrastructure decision](../adr/0029-email-infrastructure-mailpit.md)
+- [ADR-0030 — BDD email parallel strategy](../adr/0030-bdd-email-parallel-strategy.md)
+- [Mailpit docs](https://mailpit.axllent.org/docs/)

documentation/MKCERT.md

@@ -0,0 +1,120 @@
+# mkcert: Local HTTPS for Development
+
+## Overview
+
+This document describes how to set up local HTTPS development certificates using `mkcert`.
+
+OIDC providers **reject `http://localhost` as a redirect URI** by default for security reasons. To test OAuth 2.0 / OpenID Connect flows locally, the development server must be accessible via HTTPS. `mkcert` provides a zero-configuration local Certificate Authority that generates trusted certificates for localhost and custom domains.
+
+This setup is a prerequisite for **ADR-0028 Phase B** (OpenID Connect Authorization Code flow).
+
+## Why mkcert
+
+- **Trusted locally**: Certificates are automatically trusted by the system root store (macOS, Linux, Windows)
+- **No configuration**: Single commands to create and install the CA
+- **Local-only**: Certificates are valid only for localhost development, never exposed to production
+- **Industry standard**: Widely adopted tool for local HTTPS development
+
+## Installation
+
+### macOS (Homebrew)
+
+```bash
+brew install mkcert
+mkcert -install
+```
+
+The `mkcert -install` command creates and installs a local Certificate Authority in your system trust store.
+
+### Linux
+
+See [mkcert GitHub](https://github.com/FiloSottile/mkcert#installation) for distribution-specific instructions.
+
+### Windows
+
+See [mkcert GitHub](https://github.com/FiloSottile/mkcert#installation) for Windows installation.
+
+## Generate Certificates
+
+Use the provided Make target to generate certificates for localhost development:
+
+```bash
+make cert
+```
+
+This runs the following command:
+
+```bash
+mkcert -cert-file ./certs/dev-cert.pem -key-file ./certs/dev-key.pem localhost 127.0.0.1 ::1
+```
+
+### Output Files
+
+| File | Description |
+|------|-------------|
+| `./certs/dev-cert.pem` | TLS certificate for localhost, 127.0.0.1, and ::1 |
+| `./certs/dev-key.pem` | Private key for the certificate |
+
+Both files are created in the `./certs/` directory at the project root.
+
+## Use in Development
+
+Once certificates are generated, start the server with TLS enabled:
+
+```bash
+./bin/server --tls-cert ./certs/dev-cert.pem --tls-key ./certs/dev-key.pem
+```
+
+> **Note**: The `--tls-cert` and `--tls-key` flags are **not yet implemented** — this is planned for ADR-0028 Phase B.4. The Makefile and certificate generation are prepared in advance so that when the server TLS support is added, the certificates are ready.
+
+The server will then be accessible at:
+- `https://localhost:8080` (or the configured port)
+- `https://127.0.0.1:8080`
+- `https://[::1]:8080`
+
+All OIDC callback URLs must use HTTPS with one of these hostnames.
+
+## Clean Up
+
+To remove generated certificates:
+
+```bash
+make clean-cert
+```
+
+This deletes the entire `./certs/` directory.
+
+## .gitignore
+
+The `certs/` directory contains locally-generated certificates and **must not be committed** to version control.
+
+Ensure `certs/` is in your `.gitignore`. If it is not already present, add it:
+
+```bash
+echo "certs/" >> .gitignore
+```
+
+## Cross-References
+
+- [ADR-0028: Passwordless authentication: magic link → OpenID Connect](../adr/0028-passwordless-auth-migration.md) — Phase B describes the OIDC implementation that requires HTTPS
+- [mkcert GitHub Repository](https://github.com/FiloSottile/mkcert) — Official documentation
+
+## Troubleshooting
+
+### "mkcert not found" when running `make cert`
+
+Ensure `mkcert` is installed and available in your `PATH`. The Makefile checks for this and will display an error message if `mkcert` is not found.
+
+### Certificate not trusted by browser
+
+Run `mkcert -install` again. On macOS, you may need to restart your browser completely (close all windows, not just tabs).
+
+### Port already in use
+
+If another process is using the port (e.g., a non-TLS server on port 8080), stop that process first or configure the server to use a different port.
+
+## See Also
+
+- `make help` — List all available Make targets
+- [documentation/API.md](API.md) — API endpoints reference
+- [documentation/BDD_GUIDE.md](BDD_GUIDE.md) — BDD testing guide

documentation/PHASE_B_ROADMAP.md

@@ -0,0 +1,137 @@
+# ADR-0028 Phase B Roadmap
+
+**Document ID:** PHASE_B_ROADMAP
+**Date:** 2026-05-05 evening
+**Status:** In Progress
+**Author:** AI Agent (vibe/batch4-task-b-phase-b-roadmap)
+
+---
+
+## Status as of 2026-05-05 evening
+
+- [x] ADR-0028 Phase A complete (PRs #59-#63, #65)
+- [x] Phase B.1 OIDC config (PR #64)
+- [x] Phase B prep : pkg/auth skeleton (PR #69) + mkcert doc (PR #68)
+- [ ] Phase B.3 not yet started
+
+---
+
+## Remaining work
+
+Phase B delivers OpenID Connect Authorization Code flow with PKCE. Work is organized into **3 shippable phases**, each deliverable as an independent PR.
+
+### Phase B.3 — OIDC client implementation
+- **Goal:** Implement the core OIDC client methods in `pkg/auth/oidc.go`
+- **Tasks:**
+  - `Discover()`: HTTP GET to `/.well-known/openid-configuration`, parse + cache discovery document
+  - `RefreshJWKS()`: HTTP GET to JWKS URI, parse RSA public keys, cache with TTL
+  - `ExchangeCode()`: POST to token endpoint with code + PKCE verifier, return TokenResponse
+  - `ValidateIDToken()`: Verify signature against JWKS, validate standard claims (iss, aud, exp, iat)
+- **LOE:** ~200 lines of Go + unit tests
+- **Dependencies:** None (uses standard library `crypto/rsa`, `encoding/jwt`)
+- **Deliverable:** 1 PR
+
+### Phase B.4 — OIDC HTTP handlers
+- **Goal:** Add OIDC flow endpoints and wire them into the server
+- **Tasks:**
+  - Create `pkg/user/api/oidc_handler.go`
+  - `GET /api/v1/auth/oidc/start`:
+    - Generate state (CSRF protection) + PKCE verifier + challenge
+    - Store state + verifier (cookie or short-lived in-memory store)
+    - Redirect to provider's authorization endpoint
+  - `GET /api/v1/auth/oidc/callback`:
+    - Validate state parameter matches stored state
+    - Exchange code for tokens (calls B.3 client)
+    - Validate id_token (calls B.3 client)
+    - Issue internal JWT (reuse existing JWT manager from ADR-0021)
+    - Return JWT in Set-Cookie + JSON body
+  - Wire routes in `pkg/server/server.go`
+- **LOE:** ~150 lines of Go + unit tests + integration tests
+- **Dependencies:** B.3 (client methods must be implemented)
+- **Prerequisite:** Run `make cert` (mkcert, from PR #68) before starting dev
+- **Deliverable:** 1 PR
+
+### Phase B.5 — BDD coverage
+- **Goal:** End-to-end OIDC testing
+- **Tasks:**
+  - Create `features/auth/oidc.feature` with scenarios:
+    - Happy path: start → provider auth → callback → JWT issued
+    - Error: state mismatch
+    - Error: invalid code
+    - Error: expired id_token
+  - Use mock OIDC provider (local in-process) OR deterministic test against Authelia/Keycloak in docker-compose
+  - Follow ADR-0030 parallel BDD strategy for email assertions
+- **LOE:** ~150 lines of Gherkin + step definitions
+- **Dependencies:** B.3 + B.4 (endpoints must be operational)
+- **Deliverable:** 1 PR
+
+---
+
+## Dependencies and order
+
+```
+B.3 (OIDC client)
+    ↓
+B.4 (HTTP handlers) —— requires B.3
+    ↓
+B.5 (BDD coverage) —— requires B.3 + B.4
+```
+
+**Note:** mkcert (PR #68) is ready. When starting B.4 development, run `make cert` once to generate local HTTPS certificates.
+
+---
+
+## Out of scope for Phase B (deferred)
+
+| Item | Target Phase | Rationale |
+|------|--------------|-----------|
+| Decommission password auth | Phase C | Separate ADR after B is in production |
+| Multi-provider (Authelia + Google) | Phase B.6 (if needed) | Single provider sufficient for MVP |
+| JWKS rotation mid-flight retry | B.3 enhancement | Handle in initial implementation |
+| Token refresh flow | Future | Not required for auth code flow MVP |
+
+---
+
+## Risk register
+
+| Risk | Mitigation | Owner |
+|------|------------|-------|
+| JWKS rotation handling | Implement refresh + retry logic; key rotation must not break mid-flight validation | B.3 implementer |
+| PKCE storage | Use signed cookie or short-lived in-memory store; document trade-offs in implementation PR | B.4 implementer |
+| Testing without real provider | Use mock OIDC server for CI; local dev uses Authelia in docker-compose | B.5 implementer |
+| State CSRF protection | Use cryptographically random state; store server-side with short TTL | B.4 implementer |
+
+---
+
+## Cross-references
+
+- [ADR-0028: Passwordless authentication: magic link → OpenID Connect](../adr/0028-passwordless-auth-migration.md)
+- [ADR-0029: Email infrastructure (Mailpit)](../adr/0029-email-infrastructure-mailpit.md)
+- [ADR-0030: BDD email parallel strategy](../adr/0030-bdd-email-parallel-strategy.md)
+- [PR #59: Email infrastructure](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/59)
+- [PR #60: BDD Mailpit helper](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/60)
+- [PR #61: magic_link_tokens table](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/61)
+- [PR #62: Magic link handlers](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/62)
+- [PR #63: Magic link BDD](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/63)
+- [PR #64: OIDC config skeleton](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/64)
+- [PR #65: Magic link cleanup loop](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/65)
+- [PR #68: mkcert documentation](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/68)
+- [PR #69: pkg/auth skeleton](https://gitea.arcodange.lab/arcodange/dance-lessons-coach/pulls/69)
+
+---
+
+## Appendix: File inventory
+
+Existing (merged):
+- `pkg/auth/oidc.go` — skeleton with TODO methods (PR #69)
+- `pkg/auth/oidc_test.go` — placeholder tests (PR #69)
+- `documentation/MKCERT.md` — mkcert setup guide (PR #68)
+- `Makefile` — includes `make cert` target (PR #68)
+
+To be created:
+- `pkg/auth/oidc.go` — complete implementation (B.3)
+- `pkg/user/api/oidc_handler.go` — HTTP handlers (B.4)
+- `pkg/server/server.go` — route wiring (B.4)
+- `features/auth/oidc.feature` — BDD scenarios (B.5)
+- `pkg/auth/oidc_test.go` — expanded unit tests (B.3)
+- `pkg/user/api/oidc_handler_test.go` — handler tests (B.4)

features/auth/magic_link.feature

@@ -0,0 +1,34 @@
+@magic-link
+Feature: Passwordless magic-link sign-in
+  As a user without a password
+  I want to sign in by clicking a link sent to my email
+  So I can access the system without typing a password
+
+  Scenario: Happy path - request, receive, consume
+    Given the server is running
+    And I have an email address for this scenario
+    When I request a magic link for my email
+    Then I should receive an email with subject "Your sign-in link"
+    And the email contains a magic link token
+    When I consume the magic link token
+    Then the consume should succeed and return a JWT
+
+  Scenario: Token cannot be consumed twice
+    Given the server is running
+    And I have an email address for this scenario
+    When I request a magic link for my email
+    And the email contains a magic link token
+    When I consume the magic link token
+    Then the consume should succeed and return a JWT
+    When I consume the magic link token
+    Then the consume should fail with 401
+
+  Scenario: Missing token returns 400
+    Given the server is running
+    When I consume an empty magic link token
+    Then the response should have status 400
+
+  Scenario: Unknown token returns 401
+    Given the server is running
+    When I consume an unknown magic link token
+    Then the consume should fail with 401

features/greet/greet.feature

@@ -15,6 +15,16 @@ Feature: Greet Service
     When I request a greeting for "John"
     Then the response should be "{\"message\":\"Hello John!\"}"
 
+  @critical @v2-gate
+  Scenario: v2 endpoint returns 404 when api.v2_enabled is disabled
+    # In the default tag-filter run (~@v2), the test server starts with
+    # v2_enabled=false. The v2EnabledGate middleware (ADR-0023 Phase 4)
+    # returns 404 with a JSON body explaining the flag state.
+    Given the server is running
+    When I send a POST request to v2 greet with name "John"
+    Then the status code should be 404
+    And the response should contain "v2 API is currently disabled"
+
   @v2 @api
   Scenario: v2 greeting with JSON POST request
     Given the server is running with v2 enabled

pkg/auth/oidc.go

@@ -0,0 +1,330 @@
+// Package auth provides OpenID Connect client primitives for the
+// dance-lessons-coach passwordless-auth migration (ADR-0028 Phase B).
+//
+// This file defines the client surface only. HTTP handlers wire-up
+// happens in pkg/user/api/oidc_handler.go (separate phase B.3).
+package auth
+
+import (
+	"context"
+	"crypto/rsa"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"math/big"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+// OIDCClient is a per-provider OIDC client.
+// Holds the discovery document + JWKS cache + OAuth code-exchange config.
+type OIDCClient struct {
+	issuerURL    string
+	clientID     string
+	clientSecret string
+	httpClient   *http.Client
+
+	// discovery document, lazy-fetched on first use
+	discoveryMu sync.RWMutex
+	discovery   *Discovery
+
+	// JWKS cache (id_token signature verification keys), refreshed periodically
+	jwksMu      sync.RWMutex
+	jwks        map[string]*rsa.PublicKey
+	jwksFetched time.Time
+}
+
+// Discovery is the subset of the .well-known/openid-configuration document we use.
+type Discovery struct {
+	Issuer                string `json:"issuer"`
+	AuthorizationEndpoint string `json:"authorization_endpoint"`
+	TokenEndpoint         string `json:"token_endpoint"`
+	JWKSUri               string `json:"jwks_uri"`
+	UserinfoEndpoint      string `json:"userinfo_endpoint,omitempty"`
+}
+
+// TokenResponse is the response from the token endpoint after code exchange.
+type TokenResponse struct {
+	AccessToken  string `json:"access_token"`
+	TokenType    string `json:"token_type"`
+	ExpiresIn    int64  `json:"expires_in"`
+	RefreshToken string `json:"refresh_token,omitempty"`
+	IDToken      string `json:"id_token"`
+	Scope        string `json:"scope,omitempty"`
+}
+
+// IDTokenClaims represents the parsed claims from an ID token.
+type IDTokenClaims struct {
+	jwt.RegisteredClaims
+	Email         string `json:"email,omitempty"`
+	EmailVerified bool   `json:"email_verified,omitempty"`
+	Name          string `json:"name,omitempty"`
+}
+
+// jwks represents the JWKS (JSON Web Key Set) response.
+type jwks struct {
+	Keys []jwk `json:"keys"`
+}
+
+// jwk represents a single JSON Web Key.
+type jwk struct {
+	Kid string `json:"kid"`
+	Kty string `json:"kty"`
+	N   string `json:"n"`
+	E   string `json:"e"`
+	Use string `json:"use,omitempty"`
+	Alg string `json:"alg,omitempty"`
+}
+
+// NewOIDCClient constructs a client. Discovery + JWKS are NOT fetched eagerly;
+// they are lazy-loaded on first use to avoid blocking server startup if the
+// provider is temporarily down.
+func NewOIDCClient(issuerURL, clientID, clientSecret string) *OIDCClient {
+	return &OIDCClient{
+		issuerURL:    issuerURL,
+		clientID:     clientID,
+		clientSecret: clientSecret,
+		httpClient:   &http.Client{Timeout: 10 * time.Second},
+		jwks:         make(map[string]*rsa.PublicKey),
+	}
+}
+
+// decodeRSAPublicKey reconstructs an *rsa.PublicKey from JWK n and e values.
+func decodeRSAPublicKey(j jwk) (*rsa.PublicKey, error) {
+	nBytes, err := base64.RawURLEncoding.DecodeString(j.N)
+	if err != nil {
+		return nil, fmt.Errorf("decode n: %w", err)
+	}
+	eBytes, err := base64.RawURLEncoding.DecodeString(j.E)
+	if err != nil {
+		return nil, fmt.Errorf("decode e: %w", err)
+	}
+	n := new(big.Int).SetBytes(nBytes)
+	e := new(big.Int).SetBytes(eBytes)
+	return &rsa.PublicKey{N: n, E: int(e.Int64())}, nil
+}
+
+// Discover fetches and caches the .well-known document. Idempotent.
+// First call: HTTP fetch + cache. Subsequent calls: cached value.
+func (c *OIDCClient) Discover(ctx context.Context) (*Discovery, error) {
+	c.discoveryMu.RLock()
+	if c.discovery != nil {
+		c.discoveryMu.RUnlock()
+		return c.discovery, nil
+	}
+	c.discoveryMu.RUnlock()
+
+	c.discoveryMu.Lock()
+	defer c.discoveryMu.Unlock()
+
+	// Double-check after acquiring write lock
+	if c.discovery != nil {
+		return c.discovery, nil
+	}
+
+	wellKnownURL := fmt.Sprintf("%s/.well-known/openid-configuration", c.issuerURL)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, wellKnownURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("create discovery request: %w", err)
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("fetch discovery: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("discovery HTTP %d", resp.StatusCode)
+	}
+
+	var disc Discovery
+	if err := json.NewDecoder(resp.Body).Decode(&disc); err != nil {
+		return nil, fmt.Errorf("decode discovery: %w", err)
+	}
+
+	c.discovery = &disc
+	return &disc, nil
+}
+
+// RefreshJWKS fetches JWKS URI, parse keys, populate jwks map.
+func (c *OIDCClient) RefreshJWKS(ctx context.Context) error {
+	// Ensure discovery is loaded
+	if c.discovery == nil {
+		if _, err := c.Discover(ctx); err != nil {
+			return fmt.Errorf("discover: %w", err)
+		}
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.discovery.JWKSUri, nil)
+	if err != nil {
+		return fmt.Errorf("create JWKS request: %w", err)
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("fetch JWKS: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("JWKS HTTP %d", resp.StatusCode)
+	}
+
+	var keySet jwks
+	if err := json.NewDecoder(resp.Body).Decode(&keySet); err != nil {
+		return fmt.Errorf("decode JWKS: %w", err)
+	}
+
+	c.jwksMu.Lock()
+	defer c.jwksMu.Unlock()
+
+	c.jwks = make(map[string]*rsa.PublicKey)
+	for _, key := range keySet.Keys {
+		if key.Kty == "RSA" {
+			pubKey, err := decodeRSAPublicKey(key)
+			if err != nil {
+				return fmt.Errorf("decode RSA key %s: %w", key.Kid, err)
+			}
+			c.jwks[key.Kid] = pubKey
+		}
+	}
+
+	c.jwksFetched = time.Now()
+	return nil
+}
+
+// ExchangeCode exchanges an authorization code for an access token and ID token.
+func (c *OIDCClient) ExchangeCode(ctx context.Context, code, codeVerifier, redirectURI string) (*TokenResponse, error) {
+	// Ensure discovery is loaded
+	if c.discovery == nil {
+		if _, err := c.Discover(ctx); err != nil {
+			return nil, fmt.Errorf("discover: %w", err)
+		}
+	}
+
+	form := url.Values{}
+	form.Set("grant_type", "authorization_code")
+	form.Set("code", code)
+	form.Set("code_verifier", codeVerifier)
+	form.Set("redirect_uri", redirectURI)
+	form.Set("client_id", c.clientID)
+	form.Set("client_secret", c.clientSecret)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.discovery.TokenEndpoint, strings.NewReader(form.Encode()))
+	if err != nil {
+		return nil, fmt.Errorf("create token request: %w", err)
+	}
+
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("exchange code: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("token HTTP %d", resp.StatusCode)
+	}
+
+	var tokenResp TokenResponse
+	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
+		return nil, fmt.Errorf("decode token response: %w", err)
+	}
+
+	return &tokenResp, nil
+}
+
+// ValidateIDToken verifies the signature and claims of an ID token.
+func (c *OIDCClient) ValidateIDToken(ctx context.Context, idToken string) (*IDTokenClaims, error) {
+	// First, parse without verification to get the kid
+	parser := jwt.NewParser()
+	unverifiedToken, _, err := parser.ParseUnverified(idToken, &IDTokenClaims{})
+	if err != nil {
+		return nil, fmt.Errorf("parse unverified token: %w", err)
+	}
+
+	claims, ok := unverifiedToken.Claims.(*IDTokenClaims)
+	if !ok {
+		return nil, fmt.Errorf("invalid claims type")
+	}
+
+	// Get kid from header
+	kid, ok := unverifiedToken.Header["kid"].(string)
+	if !ok || kid == "" {
+		return nil, fmt.Errorf("missing kid in token header")
+	}
+
+	// Get the key, refreshing JWKS if needed
+	c.jwksMu.RLock()
+	_, keyExists := c.jwks[kid]
+	c.jwksMu.RUnlock()
+
+	if !keyExists {
+		if err := c.RefreshJWKS(ctx); err != nil {
+			return nil, fmt.Errorf("refresh JWKS: %w", err)
+		}
+
+		c.jwksMu.RLock()
+		_, keyExists = c.jwks[kid]
+		c.jwksMu.RUnlock()
+
+		if !keyExists {
+			return nil, fmt.Errorf("key %s not found in JWKS", kid)
+		}
+	}
+
+	// Parse with verification
+	keyFunc := func(token *jwt.Token) (interface{}, error) {
+		if kid, ok := token.Header["kid"].(string); ok {
+			c.jwksMu.RLock()
+			defer c.jwksMu.RUnlock()
+			if key, exists := c.jwks[kid]; exists {
+				return key, nil
+			}
+		}
+		return nil, fmt.Errorf("key not found")
+	}
+
+	parsedToken, err := jwt.ParseWithClaims(idToken, &IDTokenClaims{}, keyFunc)
+	if err != nil {
+		return nil, fmt.Errorf("parse token: %w", err)
+	}
+
+	claims, ok = parsedToken.Claims.(*IDTokenClaims)
+	if !ok {
+		return nil, fmt.Errorf("invalid claims type after parse")
+	}
+
+	// Validate claims
+	if claims.Issuer != c.issuerURL {
+		return nil, fmt.Errorf("issuer mismatch: expected %s, got %s", c.issuerURL, claims.Issuer)
+	}
+
+	// Check audience contains clientID
+	audValid := false
+	if claims.Audience != nil {
+		for _, aud := range claims.Audience {
+			if aud == c.clientID {
+				audValid = true
+				break
+			}
+		}
+	}
+	if !audValid {
+		return nil, fmt.Errorf("audience does not contain client ID %s", c.clientID)
+	}
+
+	// Check expiration
+	if claims.ExpiresAt != nil && time.Now().UTC().After(claims.ExpiresAt.Time) {
+		return nil, fmt.Errorf("token expired")
+	}
+
+	return claims, nil
+}

pkg/auth/oidc_test.go

@@ -0,0 +1,431 @@
+package auth
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/base64"
+	"fmt"
+	"math/big"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+func TestNewOIDCClient(t *testing.T) {
+	c := NewOIDCClient("https://example.com", "client_id", "client_secret")
+	if c == nil {
+		t.Fatal("NewOIDCClient returned nil")
+	}
+	if c.issuerURL != "https://example.com" {
+		t.Errorf("issuerURL not set: got %q", c.issuerURL)
+	}
+}
+
+func TestDiscover_HappyPath(t *testing.T) {
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/.well-known/openid-configuration" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+			w.WriteHeader(http.StatusNotFound)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte(fmt.Sprintf(`{"issuer":"%s","authorization_endpoint":"%s/auth","token_endpoint":"%s/token","jwks_uri":"%s/jwks"}`,
+			server.URL, server.URL, server.URL, server.URL)))
+	}))
+	defer server.Close()
+
+	client := NewOIDCClient(server.URL, "client_id", "client_secret")
+	client.httpClient = server.Client()
+
+	disc, err := client.Discover(context.Background())
+	if err != nil {
+		t.Fatalf("Discover failed: %v", err)
+	}
+
+	if disc.Issuer != server.URL {
+		t.Errorf("issuer mismatch: got %s, want %s", disc.Issuer, server.URL)
+	}
+	if disc.TokenEndpoint != server.URL+"/token" {
+		t.Errorf("token endpoint mismatch: got %s", disc.TokenEndpoint)
+	}
+	if disc.JWKSUri != server.URL+"/jwks" {
+		t.Errorf("jwks_uri mismatch: got %s", disc.JWKSUri)
+	}
+}
+
+func TestDiscover_Idempotent(t *testing.T) {
+	var requestCount int32
+
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		atomic.AddInt32(&requestCount, 1)
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte(fmt.Sprintf(`{"issuer":"%s","authorization_endpoint":"%s/auth","token_endpoint":"%s/token","jwks_uri":"%s/jwks"}`,
+			server.URL, server.URL, server.URL, server.URL)))
+	}))
+	defer server.Close()
+
+	client := NewOIDCClient(server.URL, "client_id", "client_secret")
+	client.httpClient = server.Client()
+
+	// First call
+	_, err := client.Discover(context.Background())
+	if err != nil {
+		t.Fatalf("First Discover failed: %v", err)
+	}
+
+	// Second call
+	_, err = client.Discover(context.Background())
+	if err != nil {
+		t.Fatalf("Second Discover failed: %v", err)
+	}
+
+	if atomic.LoadInt32(&requestCount) != 1 {
+		t.Errorf("Expected 1 HTTP request, got %d", requestCount)
+	}
+}
+
+func generateTestRSAKey(t *testing.T) *rsa.PrivateKey {
+	t.Helper()
+	privKey, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		t.Fatalf("failed to generate RSA key: %v", err)
+	}
+	return privKey
+}
+
+func encodeRSAPublicKey(privKey *rsa.PrivateKey) (n, e string) {
+	n = base64.RawURLEncoding.EncodeToString(privKey.PublicKey.N.Bytes())
+	e = base64.RawURLEncoding.EncodeToString(big.NewInt(int64(privKey.PublicKey.E)).Bytes())
+	return n, e
+}
+
+func TestRefreshJWKS_HappyPath(t *testing.T) {
+	privKey := generateTestRSAKey(t)
+	n, e := encodeRSAPublicKey(privKey)
+
+	var discoveryCalled, jwksCalled bool
+
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/.well-known/openid-configuration" {
+			discoveryCalled = true
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"issuer":"%s","authorization_endpoint":"%s/auth","token_endpoint":"%s/token","jwks_uri":"%s/jwks"}`,
+				server.URL, server.URL, server.URL, server.URL)))
+			return
+		}
+		if r.URL.Path == "/jwks" {
+			jwksCalled = true
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"keys":[{"kid":"test-key-id","kty":"RSA","use":"sig","alg":"RS256","n":"%s","e":"%s"}]}`, n, e)))
+			return
+		}
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer server.Close()
+
+	client := NewOIDCClient(server.URL, "client_id", "client_secret")
+	client.httpClient = server.Client()
+
+	// First discover to populate discovery
+	_, err := client.Discover(context.Background())
+	if err != nil {
+		t.Fatalf("Discover failed: %v", err)
+	}
+
+	// Now refresh JWKS
+	err = client.RefreshJWKS(context.Background())
+	if err != nil {
+		t.Fatalf("RefreshJWKS failed: %v", err)
+	}
+
+	if !discoveryCalled {
+		t.Error("discovery endpoint was not called")
+	}
+	if !jwksCalled {
+		t.Error("jwks endpoint was not called")
+	}
+
+	// Check that jwks was populated
+	client.jwksMu.RLock()
+	defer client.jwksMu.RUnlock()
+
+	if len(client.jwks) != 1 {
+		t.Errorf("expected 1 key in jwks, got %d", len(client.jwks))
+	}
+
+	if _, exists := client.jwks["test-key-id"]; !exists {
+		t.Error("test-key-id not found in jwks")
+	}
+}
+
+func TestExchangeCode_HappyPath(t *testing.T) {
+	tokenResponseJSON := `{"access_token":"access-token-123","id_token":"id-token-456","token_type":"Bearer","expires_in":3600}`
+
+	var receivedForm url.Values
+
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/.well-known/openid-configuration" {
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"issuer":"%s","authorization_endpoint":"%s/auth","token_endpoint":"%s/token","jwks_uri":"%s/jwks"}`,
+				server.URL, server.URL, server.URL, server.URL)))
+			return
+		}
+		if r.URL.Path == "/token" {
+			if r.Method != http.MethodPost {
+				t.Errorf("expected POST, got %s", r.Method)
+				w.WriteHeader(http.StatusMethodNotAllowed)
+				return
+			}
+			if r.Header.Get("Content-Type") != "application/x-www-form-urlencoded" {
+				t.Errorf("expected Content-Type application/x-www-form-urlencoded, got %s", r.Header.Get("Content-Type"))
+				w.WriteHeader(http.StatusBadRequest)
+				return
+			}
+
+			err := r.ParseForm()
+			if err != nil {
+				t.Errorf("failed to parse form: %v", err)
+				w.WriteHeader(http.StatusBadRequest)
+				return
+			}
+			receivedForm = r.Form
+
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(tokenResponseJSON))
+			return
+		}
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer server.Close()
+
+	client := NewOIDCClient(server.URL, "client_id", "client_secret")
+	client.httpClient = server.Client()
+
+	// Discover first to populate discovery
+	_, err := client.Discover(context.Background())
+	if err != nil {
+		t.Fatalf("Discover failed: %v", err)
+	}
+
+	resp, err := client.ExchangeCode(context.Background(), "auth-code-789", "code-verifier-123", "https://app.example.com/callback")
+	if err != nil {
+		t.Fatalf("ExchangeCode failed: %v", err)
+	}
+
+	if resp.AccessToken != "access-token-123" {
+		t.Errorf("access token mismatch: got %s", resp.AccessToken)
+	}
+	if resp.IDToken != "id-token-456" {
+		t.Errorf("id token mismatch: got %s", resp.IDToken)
+	}
+	if resp.TokenType != "Bearer" {
+		t.Errorf("token type mismatch: got %s", resp.TokenType)
+	}
+
+	// Check form values
+	if receivedForm.Get("grant_type") != "authorization_code" {
+		t.Errorf("grant_type mismatch: got %s", receivedForm.Get("grant_type"))
+	}
+	if receivedForm.Get("code") != "auth-code-789" {
+		t.Errorf("code mismatch: got %s", receivedForm.Get("code"))
+	}
+	if receivedForm.Get("code_verifier") != "code-verifier-123" {
+		t.Errorf("code_verifier mismatch: got %s", receivedForm.Get("code_verifier"))
+	}
+	if receivedForm.Get("redirect_uri") != "https://app.example.com/callback" {
+		t.Errorf("redirect_uri mismatch: got %s", receivedForm.Get("redirect_uri"))
+	}
+	if receivedForm.Get("client_id") != "client_id" {
+		t.Errorf("client_id mismatch: got %s", receivedForm.Get("client_id"))
+	}
+	if receivedForm.Get("client_secret") != "client_secret" {
+		t.Errorf("client_secret mismatch: got %s", receivedForm.Get("client_secret"))
+	}
+}
+
+func TestValidateIDToken_HappyPath(t *testing.T) {
+	privKey := generateTestRSAKey(t)
+	n, e := encodeRSAPublicKey(privKey)
+
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/.well-known/openid-configuration" {
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"issuer":"%s","authorization_endpoint":"%s/auth","token_endpoint":"%s/token","jwks_uri":"%s/jwks"}`,
+				server.URL, server.URL, server.URL, server.URL)))
+			return
+		}
+		if r.URL.Path == "/jwks" {
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"keys":[{"kid":"test-key-id","kty":"RSA","use":"sig","alg":"RS256","n":"%s","e":"%s"}]}`, n, e)))
+			return
+		}
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer server.Close()
+
+	client := NewOIDCClient(server.URL, "client_id", "client_secret")
+	client.httpClient = server.Client()
+
+	// Create and sign a JWT
+	token := jwt.NewWithClaims(jwt.SigningMethodRS256, &IDTokenClaims{
+		RegisteredClaims: jwt.RegisteredClaims{
+			Issuer:    server.URL,
+			Audience:  jwt.ClaimStrings{"client_id"},
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Hour)),
+			IssuedAt:  jwt.NewNumericDate(time.Now()),
+			Subject:   "user-123",
+		},
+		Email:         "user@example.com",
+		EmailVerified: true,
+		Name:          "Test User",
+	})
+	token.Header["kid"] = "test-key-id"
+
+	signedToken, err := token.SignedString(privKey)
+	if err != nil {
+		t.Fatalf("failed to sign token: %v", err)
+	}
+
+	// Validate the token
+	claims, err := client.ValidateIDToken(context.Background(), signedToken)
+	if err != nil {
+		t.Fatalf("ValidateIDToken failed: %v", err)
+	}
+
+	if claims.Issuer != server.URL {
+		t.Errorf("issuer mismatch: got %s, want %s", claims.Issuer, server.URL)
+	}
+	if claims.Subject != "user-123" {
+		t.Errorf("subject mismatch: got %s", claims.Subject)
+	}
+	if claims.Email != "user@example.com" {
+		t.Errorf("email mismatch: got %s", claims.Email)
+	}
+	if !claims.EmailVerified {
+		t.Error("email_verified should be true")
+	}
+	if claims.Name != "Test User" {
+		t.Errorf("name mismatch: got %s", claims.Name)
+	}
+}
+
+func TestValidateIDToken_RejectsExpired(t *testing.T) {
+	privKey := generateTestRSAKey(t)
+	n, e := encodeRSAPublicKey(privKey)
+
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/.well-known/openid-configuration" {
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"issuer":"%s","authorization_endpoint":"%s/auth","token_endpoint":"%s/token","jwks_uri":"%s/jwks"}`,
+				server.URL, server.URL, server.URL, server.URL)))
+			return
+		}
+		if r.URL.Path == "/jwks" {
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"keys":[{"kid":"test-key-id","kty":"RSA","use":"sig","alg":"RS256","n":"%s","e":"%s"}]}`, n, e)))
+			return
+		}
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer server.Close()
+
+	client := NewOIDCClient(server.URL, "client_id", "client_secret")
+	client.httpClient = server.Client()
+
+	// Create an expired JWT
+	token := jwt.NewWithClaims(jwt.SigningMethodRS256, &IDTokenClaims{
+		RegisteredClaims: jwt.RegisteredClaims{
+			Issuer:    server.URL,
+			Audience:  jwt.ClaimStrings{"client_id"},
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(-time.Hour)), // Expired 1 hour ago
+			IssuedAt:  jwt.NewNumericDate(time.Now().Add(-2 * time.Hour)),
+			Subject:   "user-123",
+		},
+	})
+	token.Header["kid"] = "test-key-id"
+
+	signedToken, err := token.SignedString(privKey)
+	if err != nil {
+		t.Fatalf("failed to sign token: %v", err)
+	}
+
+	// Should fail due to expired token
+	_, err = client.ValidateIDToken(context.Background(), signedToken)
+	if err == nil {
+		t.Error("expected error for expired token, got nil")
+	}
+}
+
+func TestValidateIDToken_RejectsWrongIssuer(t *testing.T) {
+	privKey := generateTestRSAKey(t)
+	n, e := encodeRSAPublicKey(privKey)
+
+	wrongIssuer := "https://wrong-provider.example.com"
+
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/.well-known/openid-configuration" {
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"issuer":"%s","authorization_endpoint":"%s/auth","token_endpoint":"%s/token","jwks_uri":"%s/jwks"}`,
+				server.URL, server.URL, server.URL, server.URL)))
+			return
+		}
+		if r.URL.Path == "/jwks" {
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(fmt.Sprintf(`{"keys":[{"kid":"test-key-id","kty":"RSA","use":"sig","alg":"RS256","n":"%s","e":"%s"}]}`, n, e)))
+			return
+		}
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer server.Close()
+
+	client := NewOIDCClient(server.URL, "client_id", "client_secret")
+	client.httpClient = server.Client()
+
+	// Create a JWT with wrong issuer
+	token := jwt.NewWithClaims(jwt.SigningMethodRS256, &IDTokenClaims{
+		RegisteredClaims: jwt.RegisteredClaims{
+			Issuer:    wrongIssuer,
+			Audience:  jwt.ClaimStrings{"client_id"},
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Hour)),
+			IssuedAt:  jwt.NewNumericDate(time.Now()),
+			Subject:   "user-123",
+		},
+	})
+	token.Header["kid"] = "test-key-id"
+
+	signedToken, err := token.SignedString(privKey)
+	if err != nil {
+		t.Fatalf("failed to sign token: %v", err)
+	}
+
+	// Should fail due to issuer mismatch
+	_, err = client.ValidateIDToken(context.Background(), signedToken)
+	if err == nil {
+		t.Error("expected error for wrong issuer, got nil")
+	}
+}

pkg/bdd/mailpit/client.go

@@ -0,0 +1,180 @@
+// Package mailpit is a thin client for the local Mailpit HTTP API,
+// used by BDD scenarios to assert on emails sent during a test.
+//
+// Per ADR-0030 (BDD email parallel strategy), each scenario uses a
+// unique recipient address so parallel scenarios cannot interfere.
+// The client exposes per-recipient query + delete + await operations.
+//
+// Production code MUST NOT depend on this package. It lives under
+// pkg/bdd/ specifically to signal "test-only".
+package mailpit
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+// DefaultBaseURL is the local Mailpit HTTP API root used by the
+// docker-compose service (cf. ADR-0029).
+const DefaultBaseURL = "http://localhost:8025"
+
+// Client is a Mailpit HTTP API client. Safe for concurrent use.
+type Client struct {
+	BaseURL string
+	HTTP    *http.Client
+}
+
+// NewClient returns a Client pointing at the local Mailpit. The HTTP
+// client has a 5-second per-call timeout to fail fast in test setups
+// where Mailpit is down.
+func NewClient() *Client {
+	return &Client{
+		BaseURL: DefaultBaseURL,
+		HTTP:    &http.Client{Timeout: 5 * time.Second},
+	}
+}
+
+// Message is the metadata + body view returned by the Mailpit detail
+// endpoint. Fields are a subset of what Mailpit returns — only what
+// BDD scenarios need to assert on.
+type Message struct {
+	ID      string                 `json:"ID"`
+	From    Address                `json:"From"`
+	To      []Address              `json:"To"`
+	Subject string                 `json:"Subject"`
+	Text    string                 `json:"Text"`
+	HTML    string                 `json:"HTML"`
+	Date    time.Time              `json:"Date"`
+	Headers map[string]interface{} `json:"-"` // populated only via the Headers() helper
+}
+
+// Address is a Mailpit-formatted email address.
+type Address struct {
+	Name    string `json:"Name"`
+	Address string `json:"Address"`
+}
+
+// listResponse is the shape of GET /api/v1/messages.
+type listResponse struct {
+	Messages []messageSummary `json:"messages"`
+	Total    int              `json:"total"`
+}
+
+type messageSummary struct {
+	ID      string    `json:"ID"`
+	Subject string    `json:"Subject"`
+	Created time.Time `json:"Created"`
+}
+
+// MessagesTo returns the list of message IDs currently in Mailpit
+// addressed to the given recipient. Empty slice + nil error means
+// "no messages yet".
+func (c *Client) MessagesTo(ctx context.Context, to string) ([]string, error) {
+	// Mailpit's /api/v1/search supports the to:<addr> filter ; the more
+	// obvious-looking /api/v1/messages does NOT (the `query` param there
+	// is for pagination, not filtering — verified empirically 2026-05-05).
+	u := fmt.Sprintf("%s/api/v1/search?query=%s",
+		strings.TrimRight(c.BaseURL, "/"),
+		url.QueryEscape("to:"+to))
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := c.HTTP.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("mailpit list: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("mailpit list: HTTP %d", resp.StatusCode)
+	}
+	var list listResponse
+	if err := json.NewDecoder(resp.Body).Decode(&list); err != nil {
+		return nil, fmt.Errorf("mailpit list decode: %w", err)
+	}
+	ids := make([]string, 0, len(list.Messages))
+	for _, m := range list.Messages {
+		ids = append(ids, m.ID)
+	}
+	return ids, nil
+}
+
+// Get fetches the full content of the message with the given ID.
+func (c *Client) Get(ctx context.Context, id string) (*Message, error) {
+	u := fmt.Sprintf("%s/api/v1/message/%s",
+		strings.TrimRight(c.BaseURL, "/"),
+		url.PathEscape(id))
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := c.HTTP.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("mailpit get: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("mailpit get %s: HTTP %d", id, resp.StatusCode)
+	}
+	var m Message
+	if err := json.NewDecoder(resp.Body).Decode(&m); err != nil {
+		return nil, fmt.Errorf("mailpit get decode: %w", err)
+	}
+	return &m, nil
+}
+
+// AwaitMessageTo polls Mailpit for a message addressed to the given
+// recipient. Returns the most recent matching message ; errors out if
+// the timeout elapses with no match. Polls every 50ms — Mailpit is
+// fast enough that this is rarely the limiting factor.
+//
+// Use this in BDD steps "Then I should receive an email ...".
+func (c *Client) AwaitMessageTo(ctx context.Context, to string, timeout time.Duration) (*Message, error) {
+	deadline := time.Now().Add(timeout)
+	for time.Now().Before(deadline) {
+		ids, err := c.MessagesTo(ctx, to)
+		if err == nil && len(ids) > 0 {
+			// Most recent first per Mailpit's default sort
+			return c.Get(ctx, ids[0])
+		}
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case <-time.After(50 * time.Millisecond):
+		}
+	}
+	return nil, fmt.Errorf("mailpit: no message for %s within %s", to, timeout)
+}
+
+// PurgeMessagesTo deletes every message addressed to the given recipient.
+// Idempotent: calling against an empty inbox is fine.
+//
+// Use this at the start of a BDD scenario to clear leftovers from
+// prior runs of the same scenario (rare given the random suffix per
+// scenario, but defensive).
+func (c *Client) PurgeMessagesTo(ctx context.Context, to string) error {
+	// Mailpit's /api/v1/search supports the to:<addr> filter ; the more
+	// obvious-looking /api/v1/messages does NOT (the `query` param there
+	// is for pagination, not filtering — verified empirically 2026-05-05).
+	u := fmt.Sprintf("%s/api/v1/search?query=%s",
+		strings.TrimRight(c.BaseURL, "/"),
+		url.QueryEscape("to:"+to))
+	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, u, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := c.HTTP.Do(req)
+	if err != nil {
+		return fmt.Errorf("mailpit delete: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusNoContent {
+		return fmt.Errorf("mailpit delete: HTTP %d", resp.StatusCode)
+	}
+	return nil
+}

pkg/bdd/mailpit/client_integration_test.go

@@ -0,0 +1,133 @@
+//go:build integration
+
+// Integration tests for the Mailpit client. Run with:
+//
+//	go test -tags integration ./pkg/bdd/mailpit/...
+//
+// Requires a running Mailpit reachable at http://localhost:8025
+// (the docker-compose service from ADR-0029).
+package mailpit
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"net/smtp"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// uniqueRecipient returns an address unique to this test run, using the
+// per-scenario-recipient pattern from ADR-0030. Two parallel test runs
+// generate different suffixes so they never see each other's messages.
+func uniqueRecipient(t *testing.T) string {
+	t.Helper()
+	var raw [4]byte
+	_, err := rand.Read(raw[:])
+	require.NoError(t, err)
+	return "integ-" + t.Name() + "-" + hex.EncodeToString(raw[:]) + "@bdd.local"
+}
+
+// sendViaSMTP submits a small email through Mailpit's SMTP port.
+// Real-wire-format path : same as the application code will use.
+func sendViaSMTP(t *testing.T, to, subject, body string) {
+	t.Helper()
+	from := "integ-test@bdd.local"
+	msg := []byte(
+		"From: " + from + "\r\n" +
+			"To: " + to + "\r\n" +
+			"Subject: " + subject + "\r\n" +
+			"\r\n" +
+			body + "\r\n",
+	)
+	err := smtp.SendMail("localhost:1025", nil, from, []string{to}, msg)
+	require.NoError(t, err, "SMTP send to local Mailpit")
+}
+
+// TestIntegration_RoundTrip validates the full path : SMTP submit →
+// Mailpit captures → client lists → client gets full body. This is
+// the smoke test for the BDD-helper contract.
+func TestIntegration_RoundTrip(t *testing.T) {
+	c := NewClient()
+	to := uniqueRecipient(t)
+
+	// Defensive cleanup before the test (in case the recipient was reused)
+	require.NoError(t, c.PurgeMessagesTo(context.Background(), to))
+
+	subject := "Integration roundtrip"
+	body := "Token: integ-token-" + strings.ReplaceAll(to, "@", "-at-")
+
+	sendViaSMTP(t, to, subject, body)
+
+	msg, err := c.AwaitMessageTo(context.Background(), to, 3*time.Second)
+	require.NoError(t, err)
+	require.NotNil(t, msg)
+
+	assert.Equal(t, subject, msg.Subject)
+	assert.Contains(t, msg.Text, "Token: integ-token-")
+	if assert.Len(t, msg.To, 1) {
+		assert.Equal(t, to, msg.To[0].Address)
+	}
+
+	// Cleanup so subsequent runs of this same test name don't accumulate
+	require.NoError(t, c.PurgeMessagesTo(context.Background(), to))
+}
+
+// TestIntegration_AwaitTimeoutWhenNoMessage confirms AwaitMessageTo
+// returns an error within the timeout when no message arrives.
+func TestIntegration_AwaitTimeoutWhenNoMessage(t *testing.T) {
+	c := NewClient()
+	to := uniqueRecipient(t) // never sent to → must time out
+
+	start := time.Now()
+	_, err := c.AwaitMessageTo(context.Background(), to, 200*time.Millisecond)
+	elapsed := time.Since(start)
+
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "no message")
+	assert.GreaterOrEqual(t, elapsed, 150*time.Millisecond, "should poll until close to timeout")
+	assert.Less(t, elapsed, 1*time.Second, "should not exceed timeout substantially")
+}
+
+// TestIntegration_PurgeIsolation proves the per-recipient query/delete
+// model from ADR-0030 : two unique recipients can have their own
+// messages without one's purge affecting the other.
+func TestIntegration_PurgeIsolation(t *testing.T) {
+	c := NewClient()
+	// Build two distinct, well-formed addresses (separate local-parts,
+	// same domain). Avoid mutating uniqueRecipient's output post-@.
+	var rawA, rawB [4]byte
+	_, _ = rand.Read(rawA[:])
+	_, _ = rand.Read(rawB[:])
+	toA := "iso-a-" + hex.EncodeToString(rawA[:]) + "@bdd.local"
+	toB := "iso-b-" + hex.EncodeToString(rawB[:]) + "@bdd.local"
+
+	sendViaSMTP(t, toA, "for A", "body A")
+	sendViaSMTP(t, toB, "for B", "body B")
+
+	// Both messages should exist
+	idsA, err := c.MessagesTo(context.Background(), toA)
+	require.NoError(t, err)
+	assert.GreaterOrEqual(t, len(idsA), 1, "A should have its message")
+	idsB, err := c.MessagesTo(context.Background(), toB)
+	require.NoError(t, err)
+	assert.GreaterOrEqual(t, len(idsB), 1, "B should have its message")
+
+	// Purge A only
+	require.NoError(t, c.PurgeMessagesTo(context.Background(), toA))
+
+	// A is empty, B is untouched
+	idsA, err = c.MessagesTo(context.Background(), toA)
+	require.NoError(t, err)
+	assert.Empty(t, idsA, "A should be empty after purge")
+	idsB, err = c.MessagesTo(context.Background(), toB)
+	require.NoError(t, err)
+	assert.GreaterOrEqual(t, len(idsB), 1, "B should still have its message")
+
+	// Cleanup B
+	require.NoError(t, c.PurgeMessagesTo(context.Background(), toB))
+}

pkg/bdd/steps/magic_link_steps.go

@@ -0,0 +1,145 @@
+package steps
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"regexp"
+	"strings"
+	"time"
+
+	"dance-lessons-coach/pkg/bdd/mailpit"
+	"dance-lessons-coach/pkg/bdd/testserver"
+)
+
+type MagicLinkSteps struct {
+	client      *testserver.Client
+	mailpit     *mailpit.Client
+	scenarioKey string
+}
+
+func NewMagicLinkSteps(client *testserver.Client) *MagicLinkSteps {
+	return &MagicLinkSteps{client: client, mailpit: mailpit.NewClient()}
+}
+
+func (s *MagicLinkSteps) SetScenarioKey(key string) { s.scenarioKey = key }
+
+func (s *MagicLinkSteps) state() *ScenarioState {
+	if s.scenarioKey == "" {
+		s.scenarioKey = "default"
+	}
+	return GetScenarioState(s.scenarioKey)
+}
+
+// sanitizeForEmail keeps only [a-z0-9-] from the scenario key
+func sanitizeForEmail(s string) string {
+	if s == "" {
+		return "scn"
+	}
+	var b strings.Builder
+	for _, r := range strings.ToLower(s) {
+		if (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '-' {
+			b.WriteRune(r)
+		}
+	}
+	if b.Len() == 0 {
+		return "scn"
+	}
+	if b.Len() > 24 {
+		return b.String()[:24]
+	}
+	return b.String()
+}
+
+// IHaveAnEmailAddressForThisScenario generates per-scenario unique recipient and stashes it in state.
+// Defensively purges Mailpit for that address.
+// Format: <scenario-key>-<8hex>@bdd.local  (cf. ADR-0030)
+func (s *MagicLinkSteps) IHaveAnEmailAddressForThisScenario() error {
+	var raw [4]byte
+	if _, err := rand.Read(raw[:]); err != nil {
+		return err
+	}
+	addr := fmt.Sprintf("ml-%s-%s@bdd.local",
+		sanitizeForEmail(s.scenarioKey), hex.EncodeToString(raw[:]))
+	s.state().MagicLinkEmail = addr
+	return s.mailpit.PurgeMessagesTo(context.Background(), addr)
+}
+
+// IRequestAMagicLinkForMyEmail POSTs to /api/v1/auth/magic-link/request with the scenario's email.
+func (s *MagicLinkSteps) IRequestAMagicLinkForMyEmail() error {
+	return s.client.Request("POST", "/api/v1/auth/magic-link/request",
+		map[string]string{"email": s.state().MagicLinkEmail})
+}
+
+// IShouldReceiveAnEmailWithSubject waits for an email at the scenario's address; asserts subject equality.
+func (s *MagicLinkSteps) IShouldReceiveAnEmailWithSubject(subject string) error {
+	msg, err := s.mailpit.AwaitMessageTo(context.Background(), s.state().MagicLinkEmail, 5*time.Second)
+	if err != nil {
+		return fmt.Errorf("mailpit await: %w", err)
+	}
+	if msg.Subject != subject {
+		return fmt.Errorf("expected subject %q, got %q", subject, msg.Subject)
+	}
+	return nil
+}
+
+// TheEmailContainsAMagicLinkToken re-fetches most recent message, extracts token via regex, stashes in state.
+var tokenRe = regexp.MustCompile(`\?token=([A-Za-z0-9_\-]+)`)
+
+func (s *MagicLinkSteps) TheEmailContainsAMagicLinkToken() error {
+	msg, err := s.mailpit.AwaitMessageTo(context.Background(), s.state().MagicLinkEmail, 5*time.Second)
+	if err != nil {
+		return err
+	}
+	m := tokenRe.FindStringSubmatch(msg.Text)
+	if m == nil {
+		return fmt.Errorf("no token in email body: %q", msg.Text)
+	}
+	s.state().MagicLinkToken = m[1]
+	return nil
+}
+
+// IConsumeTheMagicLinkToken GETs /api/v1/auth/magic-link/consume?token=<plain>
+func (s *MagicLinkSteps) IConsumeTheMagicLinkToken() error {
+	return s.client.Request("GET",
+		"/api/v1/auth/magic-link/consume?token="+s.state().MagicLinkToken, nil)
+}
+
+// TheConsumeShouldSucceedAndReturnAJWT asserts 200 + JWT body.
+func (s *MagicLinkSteps) TheConsumeShouldSucceedAndReturnAJWT() error {
+	if c := s.client.GetLastStatusCode(); c != http.StatusOK {
+		return fmt.Errorf("expected 200, got %d body=%s", c, s.client.GetLastBody())
+	}
+	var resp struct {
+		Token string `json:"token"`
+	}
+	if err := json.Unmarshal(s.client.GetLastBody(), &resp); err != nil {
+		return err
+	}
+	if resp.Token == "" {
+		return fmt.Errorf("empty JWT in response")
+	}
+	s.state().LastToken = resp.Token
+	return nil
+}
+
+// TheConsumeShouldFailWith401 asserts 401.
+func (s *MagicLinkSteps) TheConsumeShouldFailWith401() error {
+	if c := s.client.GetLastStatusCode(); c != http.StatusUnauthorized {
+		return fmt.Errorf("expected 401, got %d body=%s", c, s.client.GetLastBody())
+	}
+	return nil
+}
+
+// IConsumeAnEmptyMagicLinkToken consumes with an empty token
+func (s *MagicLinkSteps) IConsumeAnEmptyMagicLinkToken() error {
+	return s.client.Request("GET", "/api/v1/auth/magic-link/consume?token=", nil)
+}
+
+// IConsumeAnUnknownMagicLinkToken consumes with a non-existent token
+func (s *MagicLinkSteps) IConsumeAnUnknownMagicLinkToken() error {
+	return s.client.Request("GET", "/api/v1/auth/magic-link/consume?token=unknown-token-12345", nil)
+}

pkg/bdd/steps/scenario_state.go

@@ -9,11 +9,13 @@ import (
 // ScenarioState holds per-scenario state for step definitions
 // This prevents state pollution between scenarios running in the same test process
 type ScenarioState struct {
-	LastToken  string
-	FirstToken string
-	LastUserID uint
-	LastSecret string
-	LastError  string
+	LastToken      string
+	FirstToken     string
+	LastUserID     uint
+	LastSecret     string
+	LastError      string
+	MagicLinkEmail string
+	MagicLinkToken string
 	// Add more fields as needed for other step types
 }
 

pkg/bdd/steps/steps.go

@@ -17,6 +17,7 @@ type StepContext struct {
 	jwtRetentionSteps *JWTRetentionSteps
 	configSteps       *ConfigSteps
 	rateLimitSteps    *RateLimitSteps
+	magicLinkSteps    *MagicLinkSteps
 }
 
 // NewStepContext creates a new step context
@@ -30,6 +31,7 @@ func NewStepContext(client *testserver.Client) *StepContext {
 		jwtRetentionSteps: NewJWTRetentionSteps(client),
 		configSteps:       NewConfigSteps(client),
 		rateLimitSteps:    NewRateLimitSteps(client),
+		magicLinkSteps:    NewMagicLinkSteps(client),
 	}
 }
 
@@ -67,6 +69,9 @@ func SetScenarioKeyForAllSteps(sc *StepContext, key string) {
 		if sc.rateLimitSteps != nil {
 			sc.rateLimitSteps.SetScenarioKey(key)
 		}
+		if sc.magicLinkSteps != nil {
+			sc.magicLinkSteps.SetScenarioKey(key)
+		}
 	}
 }
 
@@ -317,6 +322,17 @@ func InitializeAllSteps(ctx *godog.ScenarioContext, client *testserver.Client, s
 	ctx.Step(`^the response body should contain "([^"]*)"$`, sc.rateLimitSteps.theResponseBodyShouldContain)
 	ctx.Step(`^the response should have header "([^"]*)"$`, sc.rateLimitSteps.theResponseShouldHaveHeader)
 
+	// Magic link steps
+	ctx.Step(`^I have an email address for this scenario$`, sc.magicLinkSteps.IHaveAnEmailAddressForThisScenario)
+	ctx.Step(`^I request a magic link for my email$`, sc.magicLinkSteps.IRequestAMagicLinkForMyEmail)
+	ctx.Step(`^I should receive an email with subject "([^"]*)"$`, sc.magicLinkSteps.IShouldReceiveAnEmailWithSubject)
+	ctx.Step(`^the email contains a magic link token$`, sc.magicLinkSteps.TheEmailContainsAMagicLinkToken)
+	ctx.Step(`^I consume the magic link token$`, sc.magicLinkSteps.IConsumeTheMagicLinkToken)
+	ctx.Step(`^the consume should succeed and return a JWT$`, sc.magicLinkSteps.TheConsumeShouldSucceedAndReturnAJWT)
+	ctx.Step(`^the consume should fail with 401$`, sc.magicLinkSteps.TheConsumeShouldFailWith401)
+	ctx.Step(`^I consume an empty magic link token$`, sc.magicLinkSteps.IConsumeAnEmptyMagicLinkToken)
+	ctx.Step(`^I consume an unknown magic link token$`, sc.magicLinkSteps.IConsumeAnUnknownMagicLinkToken)
+
 	// Common steps
 	ctx.Step(`^the response should be "{\\"([^"]*)":\\"([^"]*)"}"$`, sc.commonSteps.theResponseShouldBe)
 	ctx.Step(`^the response should contain error "([^"]*)"$`, sc.commonSteps.theResponseShouldContainError)

pkg/bdd/testserver/server.go

@@ -741,8 +741,14 @@ func (s *Server) waitForServerReady() error {
 	}
 }
 
-// shouldEnableV2 determines if v2 API should be enabled for this test server
-// This is the ONLY place that reads FEATURE and GODOG_TAGS env vars
+// shouldEnableV2 determines if v2 API should be enabled for this test server.
+// This is the ONLY place that reads FEATURE and GODOG_TAGS env vars.
+//
+// 2026-05-05: previous version used strings.Contains(tags, "@v2") which
+// wrongly matched the negation `~@v2` as well. This made the "v1" greet
+// sub-test (tags `~@v2 && ~@skip`) actually run with v2 enabled, masking
+// the gate behavior we now test in feature `@v2-gate` scenario. Fixed
+// here by inspecting each && clause and checking for positive inclusion.
 func (s *Server) shouldEnableV2() bool {
 	feature := os.Getenv("FEATURE")
 
@@ -753,9 +759,19 @@ func (s *Server) shouldEnableV2() bool {
 		return false
 	}
 
-	// For greet feature: enable v2 if tags include @v2
+	// For greet feature: enable v2 if tags include `@v2` as a POSITIVE clause.
+	// Godog tag expression syntax: clauses separated by `&&` or `||`, negation
+	// via leading `~`. A positive clause matches exactly `@v2` (after trim).
 	tags := os.Getenv("GODOG_TAGS")
-	return strings.Contains(tags, "@v2")
+	for _, clause := range strings.FieldsFunc(tags, func(r rune) bool {
+		return r == '&' || r == '|' || r == ' '
+	}) {
+		clause = strings.TrimSpace(clause)
+		if clause == "@v2" {
+			return true
+		}
+	}
+	return false
 }
 
 // createTestConfig creates a test configuration
@@ -799,6 +815,20 @@ func createTestConfig(port int, v2Enabled bool) *config.Config {
 			JWT: config.JWTConfig{
 				TTL: 24 * time.Hour,
 			},
+			// Email + MagicLink defaults so the magic-link BDD scenarios
+			// (ADR-0028 Phase A.5) can send to local Mailpit. Without these
+			// the literal Config skips Viper's SetDefault and From stays
+			// empty — pkg/email then rejects the message.
+			Email: config.EmailConfig{
+				From:     "noreply@bdd.local",
+				SMTPHost: "localhost",
+				SMTPPort: 1025,
+				Timeout:  5 * time.Second,
+			},
+			MagicLink: config.MagicLinkConfig{
+				TTL:     15 * time.Minute,
+				BaseURL: "http://localhost:8080",
+			},
 		},
 		API: config.APIConfig{
 			V2Enabled: v2Enabled,

pkg/config/config.go

@@ -104,9 +104,44 @@ type APIConfig struct {
 
 // AuthConfig holds authentication configuration
 type AuthConfig struct {
-	JWTSecret           string    `mapstructure:"jwt_secret"`
-	AdminMasterPassword string    `mapstructure:"admin_master_password"`
-	JWT                 JWTConfig `mapstructure:"jwt"`
+	JWTSecret           string          `mapstructure:"jwt_secret"`
+	AdminMasterPassword string          `mapstructure:"admin_master_password"`
+	JWT                 JWTConfig       `mapstructure:"jwt"`
+	Email               EmailConfig     `mapstructure:"email"`
+	MagicLink           MagicLinkConfig `mapstructure:"magic_link"`
+	OIDC                OIDCConfig      `mapstructure:"oidc"`
+}
+
+// MagicLinkConfig holds passwordless-auth magic-link parameters (ADR-0028 Phase A).
+type MagicLinkConfig struct {
+	TTL             time.Duration `mapstructure:"ttl"`
+	BaseURL         string        `mapstructure:"base_url"`
+	CleanupInterval time.Duration `mapstructure:"cleanup_interval"`
+}
+
+// OIDCConfig holds OpenID Connect provider configuration (ADR-0028 Phase B).
+// Multiple providers are supported via a map keyed by provider name (e.g. "arcodange-sso", "google").
+type OIDCConfig struct {
+	Providers map[string]OIDCProvider `mapstructure:"providers"`
+}
+
+// OIDCProvider describes a single OIDC provider's discovery + client config.
+type OIDCProvider struct {
+	IssuerURL    string `mapstructure:"issuer_url"`
+	ClientID     string `mapstructure:"client_id"`
+	ClientSecret string `mapstructure:"client_secret"`
+}
+
+// EmailConfig holds outgoing email transport configuration.
+// Defaults match local Mailpit (cf. ADR-0029) so dev needs no extra setup.
+type EmailConfig struct {
+	From         string        `mapstructure:"from"`
+	SMTPHost     string        `mapstructure:"smtp_host"`
+	SMTPPort     int           `mapstructure:"smtp_port"`
+	SMTPUsername string        `mapstructure:"smtp_username"`
+	SMTPPassword string        `mapstructure:"smtp_password"`
+	SMTPUseTLS   bool          `mapstructure:"smtp_use_tls"`
+	Timeout      time.Duration `mapstructure:"timeout"`
 }
 
 // JWTConfig holds JWT-specific configuration
@@ -256,6 +291,22 @@ func LoadConfig() (*Config, error) {
 	v.SetDefault("auth.jwt.secret_retention.max_retention", 72*time.Hour)
 	v.SetDefault("auth.jwt.secret_retention.cleanup_interval", 1*time.Hour)
 
+	// Email defaults — match local Mailpit (ADR-0029).
+	v.SetDefault("auth.email.from", "noreply@dance-lessons-coach.local")
+	v.SetDefault("auth.email.smtp_host", "localhost")
+	v.SetDefault("auth.email.smtp_port", 1025)
+	v.SetDefault("auth.email.smtp_use_tls", false)
+	v.SetDefault("auth.email.timeout", 10*time.Second)
+
+	// Magic-link defaults (ADR-0028 Phase A).
+	v.SetDefault("auth.magic_link.ttl", 15*time.Minute)
+	v.SetDefault("auth.magic_link.base_url", "http://localhost:8080")
+	v.SetDefault("auth.magic_link.cleanup_interval", 1*time.Hour)
+
+	// OIDC defaults (ADR-0028 Phase B). Providers map is empty by default;
+	// configured per environment via config file or env vars.
+	v.SetDefault("auth.oidc.providers", map[string]interface{}{})
+
 	// Check for custom config file path via environment variable
 	if configFile := os.Getenv("DLC_CONFIG_FILE"); configFile != "" {
 		v.SetConfigFile(configFile)
@@ -301,6 +352,25 @@ func LoadConfig() (*Config, error) {
 	v.BindEnv("auth.jwt.secret_retention.retention_factor", "DLC_AUTH_JWT_SECRET_RETENTION_FACTOR")
 	v.BindEnv("auth.jwt.secret_retention.max_retention", "DLC_AUTH_JWT_SECRET_MAX_RETENTION")
 	v.BindEnv("auth.jwt.secret_retention.cleanup_interval", "DLC_AUTH_JWT_SECRET_CLEANUP_INTERVAL")
+	v.BindEnv("auth.email.from", "DLC_AUTH_EMAIL_FROM")
+	v.BindEnv("auth.email.smtp_host", "DLC_AUTH_EMAIL_SMTP_HOST")
+	v.BindEnv("auth.email.smtp_port", "DLC_AUTH_EMAIL_SMTP_PORT")
+	v.BindEnv("auth.email.smtp_username", "DLC_AUTH_EMAIL_SMTP_USERNAME")
+	v.BindEnv("auth.email.smtp_password", "DLC_AUTH_EMAIL_SMTP_PASSWORD")
+	v.BindEnv("auth.email.smtp_use_tls", "DLC_AUTH_EMAIL_SMTP_USE_TLS")
+	v.BindEnv("auth.email.timeout", "DLC_AUTH_EMAIL_TIMEOUT")
+
+	// Magic-link environment variables (ADR-0028 Phase A).
+	v.BindEnv("auth.magic_link.ttl", "DLC_AUTH_MAGIC_LINK_TTL")
+	v.BindEnv("auth.magic_link.base_url", "DLC_AUTH_MAGIC_LINK_BASE_URL")
+	v.BindEnv("auth.magic_link.cleanup_interval", "DLC_AUTH_MAGIC_LINK_CLEANUP_INTERVAL")
+
+	// OIDC environment variables (ADR-0028 Phase B). One canonical "default"
+	// provider is bindable via env; additional providers must be defined in config.yaml.
+	v.BindEnv("auth.oidc.providers.default.issuer_url", "DLC_AUTH_OIDC_ISSUER_URL")
+	v.BindEnv("auth.oidc.providers.default.client_id", "DLC_AUTH_OIDC_CLIENT_ID")
+	v.BindEnv("auth.oidc.providers.default.client_secret", "DLC_AUTH_OIDC_CLIENT_SECRET")
+
 	v.BindEnv("telemetry.sampler.type", "DLC_TELEMETRY_SAMPLER_TYPE")
 	v.BindEnv("telemetry.sampler.ratio", "DLC_TELEMETRY_SAMPLER_RATIO")
 
@@ -432,6 +502,43 @@ func (c *Config) GetAdminMasterPassword() string {
 	return c.Auth.AdminMasterPassword
 }
 
+// GetEmailConfig returns the outgoing email transport configuration.
+// Defaults match local Mailpit (localhost:1025, no TLS, no auth) per
+// ADR-0029. Used by pkg/email.NewSMTPSender.
+func (c *Config) GetEmailConfig() EmailConfig {
+	return c.Auth.Email
+}
+
+// GetMagicLinkConfig returns the passwordless-auth magic-link parameters
+// (ADR-0028 Phase A). TTL defaults to 15m, BaseURL to http://localhost:8080.
+func (c *Config) GetMagicLinkConfig() MagicLinkConfig {
+	out := c.Auth.MagicLink
+	if out.TTL <= 0 {
+		out.TTL = 15 * time.Minute
+	}
+	if out.BaseURL == "" {
+		out.BaseURL = "http://localhost:8080"
+	}
+	return out
+}
+
+// GetOIDCProviders returns the configured OIDC providers, keyed by provider name.
+// Empty map (not nil) is returned when no providers are configured.
+func (c *Config) GetOIDCProviders() map[string]OIDCProvider {
+	if c.Auth.OIDC.Providers == nil {
+		return map[string]OIDCProvider{}
+	}
+	return c.Auth.OIDC.Providers
+}
+
+// GetMagicLinkCleanupInterval returns the magic-link cleanup interval (ADR-0028 Phase A consequence).
+func (c *Config) GetMagicLinkCleanupInterval() time.Duration {
+	if c.Auth.MagicLink.CleanupInterval <= 0 {
+		return 1 * time.Hour
+	}
+	return c.Auth.MagicLink.CleanupInterval
+}
+
 // GetJWTTTL returns the JWT TTL
 func (c *Config) GetJWTTTL() time.Duration {
 	if c.Auth.JWT.TTL == 0 {

pkg/email/sender.go

@@ -0,0 +1,45 @@
+// Package email provides the abstraction over outgoing email transport.
+//
+// ADR-0029 picked Mailpit for local dev and BDD ; production sender is
+// deferred. The Sender interface is the swap point : a future production
+// adapter (AWS SES, Postmark, SendGrid) implements the same contract
+// without touching call sites.
+package email
+
+import "context"
+
+// Sender sends email messages. Implementations must be safe for
+// concurrent use — multiple goroutines may call Send simultaneously.
+type Sender interface {
+	Send(ctx context.Context, msg Message) error
+}
+
+// Message is the wire-level representation of an outgoing email.
+// Headers is for trace correlation (e.g. X-Test-Scenario-ID for BDD)
+// and arbitrary application-specific tags. Implementations include
+// these as RFC 5322 header fields.
+type Message struct {
+	// To is the recipient address (single recipient ; we don't currently
+	// support multi-recipient broadcasts — keeps the contract simple
+	// and matches the magic-link use case which is always 1:1).
+	To string
+
+	// From is the sender address. Required.
+	From string
+
+	// Subject is the RFC 5322 Subject. Required for non-empty body.
+	Subject string
+
+	// BodyText is the plain-text body. At least one of BodyText or
+	// BodyHTML must be non-empty.
+	BodyText string
+
+	// BodyHTML is the optional HTML body. When both are set, the
+	// SMTP-level message is multipart/alternative.
+	BodyHTML string
+
+	// Headers are extra RFC 5322 header fields. Keys are case-insensitive ;
+	// implementations canonicalise via textproto.CanonicalMIMEHeaderKey.
+	// Useful for BDD test correlation (X-BDD-Scenario, etc.).
+	Headers map[string]string
+}

pkg/email/smtp_sender.go

@@ -0,0 +1,155 @@
+package email
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/smtp"
+	"net/textproto"
+	"strings"
+	"time"
+)
+
+// SMTPConfig configures an SMTPSender. Defaults match local Mailpit
+// (host=localhost, port=1025, no TLS, no auth).
+type SMTPConfig struct {
+	Host     string
+	Port     int
+	Username string // empty means no AUTH
+	Password string // empty means no AUTH
+	UseTLS   bool   // STARTTLS — false for Mailpit local
+	// Timeout bounds Send to avoid hanging forever on a stuck server.
+	// Defaults to 10s when zero.
+	Timeout time.Duration
+}
+
+// SMTPSender sends mail through an SMTP server. Configured by SMTPConfig
+// with sensible Mailpit-friendly defaults.
+type SMTPSender struct {
+	cfg SMTPConfig
+}
+
+// NewSMTPSender returns a Sender backed by SMTP. The SMTPConfig is copied —
+// mutating the caller's struct after this call has no effect.
+func NewSMTPSender(cfg SMTPConfig) *SMTPSender {
+	if cfg.Host == "" {
+		cfg.Host = "localhost"
+	}
+	if cfg.Port == 0 {
+		cfg.Port = 1025
+	}
+	if cfg.Timeout == 0 {
+		cfg.Timeout = 10 * time.Second
+	}
+	return &SMTPSender{cfg: cfg}
+}
+
+// Send delivers the message via SMTP. Returns an error if the message is
+// invalid (missing required fields), if connecting / authenticating fails,
+// or if the SMTP server rejects the envelope or data.
+func (s *SMTPSender) Send(ctx context.Context, msg Message) error {
+	if err := validateMessage(msg); err != nil {
+		return err
+	}
+
+	addr := fmt.Sprintf("%s:%d", s.cfg.Host, s.cfg.Port)
+	body := buildRFC5322(msg)
+
+	var auth smtp.Auth
+	if s.cfg.Username != "" {
+		auth = smtp.PlainAuth("", s.cfg.Username, s.cfg.Password, s.cfg.Host)
+	}
+
+	// Run the SMTP exchange in a goroutine so we can honour the
+	// context's cancellation independently of net/smtp's own timeouts.
+	done := make(chan error, 1)
+	go func() {
+		done <- smtp.SendMail(addr, auth, msg.From, []string{msg.To}, body)
+	}()
+
+	select {
+	case err := <-done:
+		if err != nil {
+			return fmt.Errorf("smtp send to %s: %w", msg.To, err)
+		}
+		return nil
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-time.After(s.cfg.Timeout):
+		return errors.New("smtp send: timeout")
+	}
+}
+
+// validateMessage checks the minimum required fields for an outgoing email.
+func validateMessage(msg Message) error {
+	if msg.To == "" {
+		return errors.New("email: To is required")
+	}
+	if msg.From == "" {
+		return errors.New("email: From is required")
+	}
+	if msg.BodyText == "" && msg.BodyHTML == "" {
+		return errors.New("email: at least one of BodyText or BodyHTML is required")
+	}
+	return nil
+}
+
+// buildRFC5322 builds an RFC 5322 message body from Message. Plain-text
+// only when BodyHTML is empty ; multipart/alternative when both are set.
+//
+// Keep in mind: this is the body sent to net/smtp.SendMail, which adds
+// no headers itself. We add the canonical From, To, Subject, MIME-Version,
+// Content-Type, and any caller-provided custom headers.
+func buildRFC5322(msg Message) []byte {
+	var b strings.Builder
+
+	// Custom headers first so they show up early in the message.
+	for k, v := range msg.Headers {
+		// Normalise header name case (Foo-Bar, not foo-BAR)
+		k = textproto.CanonicalMIMEHeaderKey(k)
+		fmt.Fprintf(&b, "%s: %s\r\n", k, v)
+	}
+
+	fmt.Fprintf(&b, "From: %s\r\n", msg.From)
+	fmt.Fprintf(&b, "To: %s\r\n", msg.To)
+	fmt.Fprintf(&b, "Subject: %s\r\n", msg.Subject)
+	fmt.Fprintf(&b, "MIME-Version: 1.0\r\n")
+
+	if msg.BodyHTML == "" {
+		// Plain text only
+		fmt.Fprintf(&b, "Content-Type: text/plain; charset=utf-8\r\n")
+		fmt.Fprintf(&b, "\r\n")
+		b.WriteString(msg.BodyText)
+		return []byte(b.String())
+	}
+
+	// multipart/alternative — boundary is deterministic for tests but unique
+	// enough not to collide with body content. We don't put random bytes in
+	// the boundary because the alphabetical "alt-" prefix is recognisably
+	// ours and the rest is timestamped.
+	boundary := fmt.Sprintf("alt-%d", time.Now().UnixNano())
+	fmt.Fprintf(&b, "Content-Type: multipart/alternative; boundary=%q\r\n", boundary)
+	fmt.Fprintf(&b, "\r\n")
+
+	// Plain part (always first — clients that only render text/plain see
+	// it ; clients preferring HTML go to the HTML part)
+	fmt.Fprintf(&b, "--%s\r\n", boundary)
+	fmt.Fprintf(&b, "Content-Type: text/plain; charset=utf-8\r\n\r\n")
+	if msg.BodyText != "" {
+		b.WriteString(msg.BodyText)
+	} else {
+		b.WriteString("(see HTML version)")
+	}
+	fmt.Fprintf(&b, "\r\n")
+
+	// HTML part
+	fmt.Fprintf(&b, "--%s\r\n", boundary)
+	fmt.Fprintf(&b, "Content-Type: text/html; charset=utf-8\r\n\r\n")
+	b.WriteString(msg.BodyHTML)
+	fmt.Fprintf(&b, "\r\n")
+
+	// Close boundary
+	fmt.Fprintf(&b, "--%s--\r\n", boundary)
+
+	return []byte(b.String())
+}

pkg/email/smtp_sender_test.go

@@ -0,0 +1,123 @@
+package email
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestValidateMessage_RejectsMissingFields confirms the contract gate:
+// To, From, and at least one body are required.
+func TestValidateMessage_RejectsMissingFields(t *testing.T) {
+	cases := []struct {
+		name    string
+		msg     Message
+		wantErr string
+	}{
+		{"empty To", Message{From: "f@x", BodyText: "b"}, "To is required"},
+		{"empty From", Message{To: "t@x", BodyText: "b"}, "From is required"},
+		{"empty body", Message{To: "t@x", From: "f@x"}, "BodyText or BodyHTML"},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			err := validateMessage(tc.msg)
+			require.Error(t, err)
+			assert.Contains(t, err.Error(), tc.wantErr)
+		})
+	}
+}
+
+// TestValidateMessage_AcceptsMinimal confirms the happy path: To, From,
+// and BodyText alone is a valid message.
+func TestValidateMessage_AcceptsMinimal(t *testing.T) {
+	err := validateMessage(Message{To: "t@x", From: "f@x", BodyText: "b"})
+	assert.NoError(t, err)
+}
+
+// TestBuildRFC5322_PlainText verifies that a text-only message produces
+// a single-part text/plain RFC 5322 body with the expected headers.
+func TestBuildRFC5322_PlainText(t *testing.T) {
+	msg := Message{
+		To: "alice@example.com", From: "system@x", Subject: "Hi",
+		BodyText: "Hello Alice",
+	}
+	body := string(buildRFC5322(msg))
+
+	assert.Contains(t, body, "To: alice@example.com\r\n")
+	assert.Contains(t, body, "From: system@x\r\n")
+	assert.Contains(t, body, "Subject: Hi\r\n")
+	assert.Contains(t, body, "MIME-Version: 1.0\r\n")
+	assert.Contains(t, body, "Content-Type: text/plain; charset=utf-8\r\n")
+	assert.Contains(t, body, "\r\nHello Alice")
+	assert.NotContains(t, body, "multipart/alternative", "no HTML => no multipart")
+}
+
+// TestBuildRFC5322_Multipart verifies that text + HTML produces a
+// multipart/alternative body with both parts and a boundary close.
+func TestBuildRFC5322_Multipart(t *testing.T) {
+	msg := Message{
+		To: "alice@example.com", From: "system@x", Subject: "Hi",
+		BodyText: "Plain hello", BodyHTML: "<p>HTML hello</p>",
+	}
+	body := string(buildRFC5322(msg))
+
+	assert.Contains(t, body, "Content-Type: multipart/alternative;")
+	assert.Contains(t, body, "Plain hello", "plain part included")
+	assert.Contains(t, body, "<p>HTML hello</p>", "HTML part included")
+	// Boundary close marker
+	assert.True(t, strings.Contains(body, "--alt-") && strings.HasSuffix(strings.TrimRight(body, "\r\n"), "--"),
+		"multipart message should end with closing boundary")
+}
+
+// TestBuildRFC5322_CustomHeaders verifies that user-supplied headers
+// appear in the output with canonicalised case.
+func TestBuildRFC5322_CustomHeaders(t *testing.T) {
+	msg := Message{
+		To: "alice@example.com", From: "system@x", Subject: "Hi",
+		BodyText: "b",
+		Headers: map[string]string{
+			"x-bdd-scenario": "magic-link-happy-path",
+			"X-Trace-Id":     "abc-123",
+		},
+	}
+	body := string(buildRFC5322(msg))
+
+	assert.Contains(t, body, "X-Bdd-Scenario: magic-link-happy-path\r\n",
+		"lowercase key should be canonicalised to title-case")
+	assert.Contains(t, body, "X-Trace-Id: abc-123\r\n",
+		"already-canonical key should pass through unchanged")
+}
+
+// TestSMTPSender_DefaultsAreMailpitFriendly verifies that NewSMTPSender
+// fills in localhost:1025 and a non-zero timeout when the caller passes
+// a zero-valued SMTPConfig — which is the recommended default.
+func TestSMTPSender_DefaultsAreMailpitFriendly(t *testing.T) {
+	s := NewSMTPSender(SMTPConfig{})
+	assert.Equal(t, "localhost", s.cfg.Host)
+	assert.Equal(t, 1025, s.cfg.Port)
+	assert.Greater(t, int64(s.cfg.Timeout), int64(0), "timeout must be set, default 10s")
+	assert.Empty(t, s.cfg.Username, "default no AUTH")
+}
+
+// TestSMTPSender_ContextCancelAbortsSend confirms a cancelled ctx
+// short-circuits Send rather than waiting for the SMTP timeout.
+// We point at a port no SMTP server is listening on so the goroutine
+// will hang ; ctx cancel is what wins.
+func TestSMTPSender_ContextCancelAbortsSend(t *testing.T) {
+	s := NewSMTPSender(SMTPConfig{
+		Host: "127.0.0.1",
+		Port: 1, // privileged port, definitely no SMTP server here
+		// keep the default 10s timeout — we want ctx to win
+	})
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // pre-cancelled
+
+	err := s.Send(ctx, Message{To: "t@x", From: "f@x", BodyText: "b"})
+	require.Error(t, err)
+	// The error is ctx.Err() OR the net/smtp connect error if the goroutine
+	// happened to fail before the ctx select ran. Both are acceptable —
+	// the only unacceptable outcome is the test taking 10 seconds.
+}

pkg/server/server.go

@@ -20,6 +20,7 @@ import (
 
 	"dance-lessons-coach/pkg/cache"
 	"dance-lessons-coach/pkg/config"
+	"dance-lessons-coach/pkg/email"
 	"dance-lessons-coach/pkg/greet"
 	"dance-lessons-coach/pkg/middleware"
 	"dance-lessons-coach/pkg/telemetry"
@@ -245,6 +246,9 @@ func (s *Server) registerApiV1Routes(r chi.Router) {
 		r.Get("/{name}", s.handleGreetPath)
 	})
 
+	// Uptime endpoint
+	r.Get("/uptime", s.handleUptime)
+
 	// Register user authentication routes
 	if s.userService != nil && s.userRepo != nil {
 		// Use unified user service - much simpler!
@@ -252,6 +256,29 @@ func (s *Server) registerApiV1Routes(r chi.Router) {
 			handler := userapi.NewAuthHandler(s.userService, s.userService, s.validator)
 			r.Route("/auth", func(r chi.Router) {
 				handler.RegisterRoutes(r)
+				// Magic-link routes (ADR-0028 Phase A). Mounted only when the
+				// userRepo also implements MagicLinkRepository (PostgresRepository does).
+				if mlRepo, ok := s.userRepo.(user.MagicLinkRepository); ok {
+					emailCfg := s.config.GetEmailConfig()
+					sender := email.NewSMTPSender(email.SMTPConfig{
+						Host:     emailCfg.SMTPHost,
+						Port:     emailCfg.SMTPPort,
+						Username: emailCfg.SMTPUsername,
+						Password: emailCfg.SMTPPassword,
+						UseTLS:   emailCfg.SMTPUseTLS,
+						Timeout:  emailCfg.Timeout,
+					})
+					mlHandler := userapi.NewMagicLinkHandler(
+						mlRepo,
+						s.userService,
+						s.userRepo,
+						sender,
+						s.config.GetMagicLinkConfig(),
+						emailCfg.From,
+						s.validator,
+					)
+					mlHandler.RegisterRoutes(r)
+				}
 			})
 
 			// Register admin routes
@@ -559,6 +586,30 @@ func (s *Server) handleInfo(w http.ResponseWriter, r *http.Request) {
 	w.Write(data)
 }
 
+// UptimeResponse represents the JSON response for /api/v1/uptime
+type UptimeResponse struct {
+	StartTime     string `json:"start_time"`
+	UptimeSeconds int    `json:"uptime_seconds"`
+}
+
+// handleUptime godoc
+//
+//	@Summary		Get server uptime
+//	@Description	Returns server start time and uptime duration
+//	@Tags			System/Info
+//	@Produce		json
+//	@Success		200	{object}	UptimeResponse
+//	@Router			/v1/uptime [get]
+func (s *Server) handleUptime(w http.ResponseWriter, r *http.Request) {
+	log.Trace().Msg("Uptime check requested")
+	resp := UptimeResponse{
+		StartTime:     s.startedAt.Format(time.RFC3339),
+		UptimeSeconds: int(time.Since(s.startedAt).Seconds()),
+	}
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(resp)
+}
+
 // handleGreetQuery godoc
 //
 //	@Summary		Get greeting with cache
@@ -740,6 +791,12 @@ func (s *Server) Run() error {
 		s.userService.StartJWTSecretCleanupLoop(rootCtx, s.config.GetJWTSecretCleanupInterval())
 	}
 
+	// Start the magic-link expired-token cleanup loop (ADR-0028 Phase A consequence).
+	if mlRepo, ok := s.userRepo.(user.MagicLinkRepository); ok {
+		runner := user.NewMagicLinkCleanupRunner(mlRepo)
+		runner.StartCleanupLoop(rootCtx, s.config.GetMagicLinkCleanupInterval())
+	}
+
 	// Wire the sampler hot-reload callback (ADR-0023 Phase 3, sub-phase 3.3).
 	// telemetrySetup is non-nil only when telemetry was successfully initialized
 	// at startup — hot-reloading telemetry-on is out of scope (see ADR-0023).

pkg/server/uptime_test.go

@@ -0,0 +1,81 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"dance-lessons-coach/pkg/config"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHandleUptime(t *testing.T) {
+	// Setup with a known start time
+	cfg := &config.Config{}
+	// We need to create a server and then set its startedAt to a known time
+	// Since NewServer sets startedAt to time.Now(), we'll create the server
+	// and then use reflection or we can use NewServerWithUserRepo which also sets startedAt
+	s := NewServer(cfg, context.Background())
+
+	// Set a fixed start time for deterministic testing
+	// We can't directly set s.startedAt since it's unexported, but we can test
+	// that the handler uses the server's startedAt
+	// The test will verify the structure and that uptime_seconds is >= 0
+
+	// Create request
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/uptime", nil)
+	w := httptest.NewRecorder()
+
+	// Call handler
+	s.handleUptime(w, req)
+
+	// Check status code
+	assert.Equal(t, http.StatusOK, w.Code)
+
+	// Check content type
+	assert.Equal(t, "application/json", w.Header().Get("Content-Type"))
+
+	// Decode response
+	var resp UptimeResponse
+	err := json.NewDecoder(w.Body).Decode(&resp)
+	assert.NoError(t, err)
+
+	// Assert fields
+	assert.NotEmpty(t, resp.StartTime)
+	// Verify start_time is in RFC3339 format
+	_, err = time.Parse(time.RFC3339, resp.StartTime)
+	assert.NoError(t, err)
+	assert.GreaterOrEqual(t, resp.UptimeSeconds, 0)
+}
+
+func TestHandleUptime_Deterministic(t *testing.T) {
+	// For a more deterministic test, we would need to be able to set startedAt
+	// Since startedAt is unexported, we test the behavior with a known server
+	// that was just created (uptime should be very small)
+	cfg := &config.Config{}
+	s := NewServer(cfg, context.Background())
+
+	// Small delay to ensure uptime is at least 0 seconds
+	time.Sleep(10 * time.Millisecond)
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/uptime", nil)
+	w := httptest.NewRecorder()
+
+	s.handleUptime(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+
+	var resp UptimeResponse
+	err := json.NewDecoder(w.Body).Decode(&resp)
+	assert.NoError(t, err)
+
+	// Uptime should be at least 0 (it's int() of seconds, so minimum is 0)
+	assert.GreaterOrEqual(t, resp.UptimeSeconds, 0)
+	// Start time should be parseable
+	_, err = time.Parse(time.RFC3339, resp.StartTime)
+	assert.NoError(t, err)
+}

pkg/user/api/magic_link_handler.go

@@ -0,0 +1,277 @@
+package api
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"dance-lessons-coach/pkg/config"
+	"dance-lessons-coach/pkg/email"
+	"dance-lessons-coach/pkg/user"
+	"dance-lessons-coach/pkg/validation"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/rs/zerolog/log"
+)
+
+// MagicLinkHandler exposes the passwordless-auth endpoints described
+// in ADR-0028 Phase A : `POST /magic-link/request` and
+// `GET /magic-link/consume?token=...`.
+type MagicLinkHandler struct {
+	tokens      user.MagicLinkRepository
+	users       user.UserService
+	repo        user.UserRepository // for GetUserByUsername (sign-up flow)
+	sender      email.Sender
+	cfg         config.MagicLinkConfig
+	emailFrom   string
+	validator   *validation.Validator
+	clock       func() time.Time
+	newPassword func() (string, error)
+}
+
+// NewMagicLinkHandler wires the handler. emailFrom must be the From
+// address (typically cfg.GetEmailConfig().From).
+func NewMagicLinkHandler(
+	tokens user.MagicLinkRepository,
+	users user.UserService,
+	repo user.UserRepository,
+	sender email.Sender,
+	cfg config.MagicLinkConfig,
+	emailFrom string,
+	validator *validation.Validator,
+) *MagicLinkHandler {
+	return &MagicLinkHandler{
+		tokens:    tokens,
+		users:     users,
+		repo:      repo,
+		sender:    sender,
+		cfg:       cfg,
+		emailFrom: emailFrom,
+		validator: validator,
+		clock:     time.Now,
+		newPassword: func() (string, error) {
+			// 32 bytes = 256 bits of entropy. Encoded as 64 hex chars
+			// (well under bcrypt's 72-byte input limit; 48 bytes -> 96
+			// hex chars overflowed and broke first-link signup).
+			var raw [32]byte
+			if _, err := rand.Read(raw[:]); err != nil {
+				return "", err
+			}
+			return hex.EncodeToString(raw[:]), nil
+		},
+	}
+}
+
+// RegisterRoutes mounts the two endpoints on the provided router.
+func (h *MagicLinkHandler) RegisterRoutes(router chi.Router) {
+	router.Post("/magic-link/request", h.handleRequest)
+	router.Get("/magic-link/consume", h.handleConsume)
+}
+
+// MagicLinkRequest is the body of POST /magic-link/request.
+type MagicLinkRequest struct {
+	Email string `json:"email" validate:"required,email,max=255"`
+}
+
+// MagicLinkResponse is the response shape for both endpoints.
+type MagicLinkResponse struct {
+	Message string `json:"message"`
+	Token   string `json:"token,omitempty"`
+}
+
+// handleRequest godoc
+//
+//	@Summary		Request a magic link
+//	@Description	Generates a passwordless-auth one-time token and emails it. Always 200 to prevent email enumeration.
+//	@Tags			API/v1/User
+//	@Accept			json
+//	@Produce		json
+//	@Param			request	body		MagicLinkRequest	true	"Email address"
+//	@Success		200		{object}	MagicLinkResponse	"Email queued (or silently dropped)"
+//	@Failure		400		{object}	map[string]string	"Invalid request body"
+//	@Router			/v1/auth/magic-link/request [post]
+func (h *MagicLinkHandler) handleRequest(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+
+	var req MagicLinkRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, `{"error":"invalid_request","message":"Invalid JSON request body"}`, http.StatusBadRequest)
+		return
+	}
+	if h.validator != nil {
+		if err := h.validator.Validate(req); err != nil {
+			h.writeValidationError(w, err)
+			return
+		}
+	}
+
+	addr := strings.ToLower(strings.TrimSpace(req.Email))
+
+	plain, hashHex, err := user.GenerateMagicLinkToken()
+	if err != nil {
+		log.Error().Ctx(ctx).Err(err).Msg("magic link request: rand failed")
+		http.Error(w, `{"error":"server_error","message":"Failed to generate token"}`, http.StatusInternalServerError)
+		return
+	}
+
+	now := h.clock()
+	tok := &user.MagicLinkToken{
+		Email:     addr,
+		TokenHash: hashHex,
+		ExpiresAt: now.Add(h.cfg.TTL),
+	}
+	if err := h.tokens.CreateMagicLinkToken(ctx, tok); err != nil {
+		log.Error().Ctx(ctx).Err(err).Str("email", addr).Msg("magic link request: persist failed")
+		writeJSON(w, http.StatusOK, MagicLinkResponse{Message: "If that email is valid, a link has been sent."})
+		return
+	}
+
+	link := buildMagicLinkURL(h.cfg.BaseURL, plain)
+	subject := "Your sign-in link"
+	bodyText := fmt.Sprintf("Sign in by clicking the link below.\n\n%s\n\nThe link is valid for %s and can only be used once.\nIf you did not request this, ignore this email.\n", link, h.cfg.TTL)
+	bodyHTML := fmt.Sprintf(`<p>Sign in by clicking the link below.</p><p><a href="%s">%s</a></p><p>The link is valid for %s and can only be used once.<br>If you did not request this, ignore this email.</p>`, link, link, h.cfg.TTL)
+
+	msg := email.Message{
+		From:     h.emailFrom,
+		To:       addr,
+		Subject:  subject,
+		BodyText: bodyText,
+		BodyHTML: bodyHTML,
+	}
+	if err := h.sender.Send(ctx, msg); err != nil {
+		log.Error().Ctx(ctx).Err(err).Str("to", addr).Msg("magic link request: email send failed")
+	}
+	writeJSON(w, http.StatusOK, MagicLinkResponse{Message: "If that email is valid, a link has been sent."})
+}
+
+// handleConsume validates the token, marks it consumed, ensures a
+// matching User row exists (sign-up on first link), and issues a JWT.
+//
+// All failure modes (missing, expired, already-consumed) collapse to a
+// single 401 to prevent attackers distinguishing them.
+//
+//	@Summary		Consume a magic link
+//	@Description	Validates the magic-link token, ensures the user exists (signup-on-first-use), issues a JWT.
+//	@Tags			API/v1/User
+//	@Produce		json
+//	@Param			token	query		string				true	"The magic-link token"
+//	@Success		200		{object}	MagicLinkResponse	"Signed in"
+//	@Failure		400		{object}	map[string]string	"Missing token"
+//	@Failure		401		{object}	map[string]string	"Invalid or expired token"
+//	@Router			/v1/auth/magic-link/consume [get]
+func (h *MagicLinkHandler) handleConsume(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	plain := strings.TrimSpace(r.URL.Query().Get("token"))
+	if plain == "" {
+		writeJSONError(w, http.StatusBadRequest, "invalid_request", "missing token")
+		return
+	}
+
+	tok, err := h.tokens.GetMagicLinkTokenByHash(ctx, user.HashMagicLinkToken(plain))
+	if err != nil {
+		log.Error().Ctx(ctx).Err(err).Msg("magic link consume: lookup failed")
+		writeJSONError(w, http.StatusInternalServerError, "server_error", "lookup failed")
+		return
+	}
+	if tok == nil || tok.ConsumedAt != nil || h.clock().After(tok.ExpiresAt) {
+		writeJSONError(w, http.StatusUnauthorized, "invalid_token", "magic link is invalid or expired")
+		return
+	}
+
+	if err := h.tokens.MarkMagicLinkTokenConsumed(ctx, tok.ID, h.clock()); err != nil {
+		log.Error().Ctx(ctx).Err(err).Uint("id", tok.ID).Msg("magic link consume: mark failed")
+		writeJSONError(w, http.StatusInternalServerError, "server_error", "consume failed")
+		return
+	}
+
+	u, err := h.ensureUser(ctx, tok.Email)
+	if err != nil {
+		log.Error().Ctx(ctx).Err(err).Str("email", tok.Email).Msg("magic link consume: user upsert failed")
+		writeJSONError(w, http.StatusInternalServerError, "server_error", "user upsert failed")
+		return
+	}
+
+	jwt, err := h.users.GenerateJWT(ctx, u)
+	if err != nil {
+		log.Error().Ctx(ctx).Err(err).Msg("magic link consume: JWT generation failed")
+		writeJSONError(w, http.StatusInternalServerError, "server_error", "jwt generation failed")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, MagicLinkResponse{Message: "signed in", Token: jwt})
+}
+
+// ensureUser returns the user keyed on email (stored as Username),
+// creating them if absent. Newly-created users get a random unguessable
+// bcrypt-hashed password so the password endpoints stay locked out.
+func (h *MagicLinkHandler) ensureUser(ctx context.Context, email string) (*user.User, error) {
+	if h.repo != nil {
+		existing, err := h.repo.GetUserByUsername(ctx, email)
+		if err != nil {
+			return nil, err
+		}
+		if existing != nil {
+			return existing, nil
+		}
+	}
+
+	rawPass, err := h.newPassword()
+	if err != nil {
+		return nil, fmt.Errorf("magic link signup rand: %w", err)
+	}
+	hash, err := h.users.HashPassword(ctx, rawPass)
+	if err != nil {
+		return nil, fmt.Errorf("magic link signup hash: %w", err)
+	}
+	u := &user.User{
+		Username:     email,
+		PasswordHash: hash,
+		IsAdmin:      false,
+	}
+	if err := h.users.CreateUser(ctx, u); err != nil {
+		return nil, fmt.Errorf("magic link signup create: %w", err)
+	}
+	if h.repo != nil {
+		return h.repo.GetUserByUsername(ctx, email)
+	}
+	return u, nil
+}
+
+func (h *MagicLinkHandler) writeValidationError(w http.ResponseWriter, err error) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusBadRequest)
+	var ve *validation.ValidationError
+	if errors.As(err, &ve) {
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"error":   "validation_failed",
+			"message": "Invalid request data",
+			"details": ve.Messages,
+		})
+		return
+	}
+	_ = json.NewEncoder(w).Encode(map[string]any{
+		"error":   "validation_failed",
+		"message": err.Error(),
+	})
+}
+
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+func writeJSONError(w http.ResponseWriter, status int, code, msg string) {
+	writeJSON(w, status, map[string]string{"error": code, "message": msg})
+}
+
+func buildMagicLinkURL(baseURL, token string) string {
+	base := strings.TrimRight(baseURL, "/")
+	return fmt.Sprintf("%s/api/v1/auth/magic-link/consume?token=%s", base, token)
+}

pkg/user/api/magic_link_handler_test.go

@@ -0,0 +1,371 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"dance-lessons-coach/pkg/config"
+	"dance-lessons-coach/pkg/email"
+	"dance-lessons-coach/pkg/user"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// fakeMLRepo is an in-memory MagicLinkRepository for the handler tests.
+type fakeMLRepo struct {
+	mu     sync.Mutex
+	tokens map[string]*user.MagicLinkToken // key: TokenHash
+	nextID uint
+	failOn string // "create" / "get" / "mark" / "" (none)
+}
+
+func newFakeMLRepo() *fakeMLRepo {
+	return &fakeMLRepo{tokens: map[string]*user.MagicLinkToken{}}
+}
+
+func (r *fakeMLRepo) CreateMagicLinkToken(_ context.Context, t *user.MagicLinkToken) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.failOn == "create" {
+		return errors.New("simulated create failure")
+	}
+	r.nextID++
+	t.ID = r.nextID
+	r.tokens[t.TokenHash] = t
+	return nil
+}
+
+func (r *fakeMLRepo) GetMagicLinkTokenByHash(_ context.Context, h string) (*user.MagicLinkToken, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.failOn == "get" {
+		return nil, errors.New("simulated get failure")
+	}
+	t, ok := r.tokens[h]
+	if !ok {
+		return nil, nil
+	}
+	cp := *t
+	return &cp, nil
+}
+
+func (r *fakeMLRepo) MarkMagicLinkTokenConsumed(_ context.Context, id uint, when time.Time) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.failOn == "mark" {
+		return errors.New("simulated mark failure")
+	}
+	for _, t := range r.tokens {
+		if t.ID == id {
+			t.ConsumedAt = &when
+			return nil
+		}
+	}
+	return errors.New("not found")
+}
+
+func (r *fakeMLRepo) DeleteExpiredMagicLinkTokens(_ context.Context, _ time.Time) (int64, error) {
+	return 0, nil
+}
+
+// fakeUserSvc is a minimal user.UserService stub.
+type fakeUserSvc struct {
+	createdUsers []*user.User
+	jwtForID     map[uint]string
+	hashCalls    int
+	failOn       string // "create" / "hash" / "jwt"
+}
+
+func newFakeUserSvc() *fakeUserSvc { return &fakeUserSvc{jwtForID: map[uint]string{}} }
+
+func (s *fakeUserSvc) Authenticate(_ context.Context, _, _ string) (*user.User, error) {
+	return nil, errors.New("not used in magic-link tests")
+}
+func (s *fakeUserSvc) GenerateJWT(_ context.Context, u *user.User) (string, error) {
+	if s.failOn == "jwt" {
+		return "", errors.New("simulated jwt failure")
+	}
+	return "jwt-for-user-" + u.Username, nil
+}
+func (s *fakeUserSvc) ValidateJWT(_ context.Context, _ string) (*user.User, error) {
+	return nil, errors.New("not used")
+}
+func (s *fakeUserSvc) AdminAuthenticate(_ context.Context, _ string) (*user.User, error) {
+	return nil, errors.New("not used")
+}
+func (s *fakeUserSvc) AddJWTSecret(_ string, _ bool, _ time.Duration)               {}
+func (s *fakeUserSvc) RotateJWTSecret(_ string)                                     {}
+func (s *fakeUserSvc) GetJWTSecretByIndex(_ int) (string, bool)                     { return "", false }
+func (s *fakeUserSvc) ResetJWTSecrets()                                             {}
+func (s *fakeUserSvc) StartJWTSecretCleanupLoop(_ context.Context, _ time.Duration) {}
+func (s *fakeUserSvc) RemoveExpiredJWTSecrets() int                                 { return 0 }
+func (s *fakeUserSvc) ListJWTSecretsInfo() []user.JWTSecretInfo                     { return nil }
+
+func (s *fakeUserSvc) UserExists(_ context.Context, username string) (bool, error) {
+	for _, u := range s.createdUsers {
+		if u.Username == username {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+func (s *fakeUserSvc) CreateUser(_ context.Context, u *user.User) error {
+	if s.failOn == "create" {
+		return errors.New("simulated create failure")
+	}
+	u.ID = uint(len(s.createdUsers) + 1)
+	cp := *u
+	s.createdUsers = append(s.createdUsers, &cp)
+	return nil
+}
+func (s *fakeUserSvc) HashPassword(_ context.Context, p string) (string, error) {
+	s.hashCalls++
+	if s.failOn == "hash" {
+		return "", errors.New("simulated hash failure")
+	}
+	return "hash:" + p, nil
+}
+func (s *fakeUserSvc) RequestPasswordReset(_ context.Context, _ string) error { return nil }
+func (s *fakeUserSvc) CompletePasswordReset(_ context.Context, _, _ string) error {
+	return nil
+}
+
+// fakeUserRepo implements user.UserRepository using fakeUserSvc's slice.
+type fakeUserRepo struct{ svc *fakeUserSvc }
+
+func (r *fakeUserRepo) CreateUser(_ context.Context, u *user.User) error {
+	return r.svc.CreateUser(context.Background(), u)
+}
+func (r *fakeUserRepo) GetUserByUsername(_ context.Context, name string) (*user.User, error) {
+	for _, u := range r.svc.createdUsers {
+		if u.Username == name {
+			cp := *u
+			return &cp, nil
+		}
+	}
+	return nil, nil
+}
+func (r *fakeUserRepo) GetUserByID(_ context.Context, _ uint) (*user.User, error) { return nil, nil }
+func (r *fakeUserRepo) UpdateUser(_ context.Context, _ *user.User) error          { return nil }
+func (r *fakeUserRepo) DeleteUser(_ context.Context, _ uint) error                { return nil }
+func (r *fakeUserRepo) AllowPasswordReset(_ context.Context, _ string) error      { return nil }
+func (r *fakeUserRepo) CompletePasswordReset(_ context.Context, _, _ string) error {
+	return nil
+}
+func (r *fakeUserRepo) UserExists(_ context.Context, name string) (bool, error) {
+	return r.svc.UserExists(context.Background(), name)
+}
+func (r *fakeUserRepo) CheckDatabaseHealth(_ context.Context) error { return nil }
+
+// recordingSender captures email.Send calls without sending anything.
+type recordingSender struct {
+	mu       sync.Mutex
+	messages []email.Message
+	failNext bool
+}
+
+func (s *recordingSender) Send(_ context.Context, m email.Message) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.failNext {
+		return errors.New("simulated send failure")
+	}
+	s.messages = append(s.messages, m)
+	return nil
+}
+
+func newHandler(t *testing.T) (*MagicLinkHandler, *fakeMLRepo, *fakeUserSvc, *recordingSender) {
+	t.Helper()
+	mlRepo := newFakeMLRepo()
+	svc := newFakeUserSvc()
+	repo := &fakeUserRepo{svc: svc}
+	sender := &recordingSender{}
+	h := NewMagicLinkHandler(
+		mlRepo, svc, repo, sender,
+		config.MagicLinkConfig{TTL: 15 * time.Minute, BaseURL: "http://test.local"},
+		"noreply@test.local",
+		nil,
+	)
+	return h, mlRepo, svc, sender
+}
+
+func mountAndRequest(h *MagicLinkHandler, method, path, body string) *httptest.ResponseRecorder {
+	r := chi.NewRouter()
+	h.RegisterRoutes(r)
+	req := httptest.NewRequest(method, path, strings.NewReader(body))
+	if body != "" {
+		req.Header.Set("Content-Type", "application/json")
+	}
+	rr := httptest.NewRecorder()
+	r.ServeHTTP(rr, req)
+	return rr
+}
+
+// TestRequest_HappyPath confirms POST /magic-link/request stores a token,
+// sends an email containing the link, and returns 200 with a generic body.
+func TestRequest_HappyPath(t *testing.T) {
+	h, mlRepo, _, sender := newHandler(t)
+
+	rr := mountAndRequest(h, http.MethodPost, "/magic-link/request", `{"email":"alice@example.com"}`)
+	require.Equal(t, http.StatusOK, rr.Code)
+	assert.Contains(t, rr.Body.String(), "If that email is valid")
+
+	// One token persisted, email lower-cased.
+	require.Len(t, mlRepo.tokens, 1)
+	for _, tok := range mlRepo.tokens {
+		assert.Equal(t, "alice@example.com", tok.Email)
+		assert.Greater(t, tok.ExpiresAt.Unix(), time.Now().Unix())
+	}
+
+	// One email sent to the same address, link points at our test base URL.
+	require.Len(t, sender.messages, 1)
+	assert.Equal(t, "alice@example.com", sender.messages[0].To)
+	assert.Contains(t, sender.messages[0].BodyText, "http://test.local/api/v1/auth/magic-link/consume?token=")
+}
+
+// TestRequest_NormalizesEmail confirms the email is lower-cased + trimmed.
+func TestRequest_NormalizesEmail(t *testing.T) {
+	h, mlRepo, _, sender := newHandler(t)
+	rr := mountAndRequest(h, http.MethodPost, "/magic-link/request", `{"email":"  Alice@Example.COM  "}`)
+	require.Equal(t, http.StatusOK, rr.Code)
+	require.Len(t, mlRepo.tokens, 1)
+	for _, tok := range mlRepo.tokens {
+		assert.Equal(t, "alice@example.com", tok.Email)
+	}
+	assert.Equal(t, "alice@example.com", sender.messages[0].To)
+}
+
+// TestRequest_BadJSON returns 400.
+func TestRequest_BadJSON(t *testing.T) {
+	h, _, _, _ := newHandler(t)
+	rr := mountAndRequest(h, http.MethodPost, "/magic-link/request", `not json`)
+	assert.Equal(t, http.StatusBadRequest, rr.Code)
+}
+
+// TestRequest_PersistFailureStillReturns200 — a DB error must NOT leak
+// to the user (would let attackers detect storage outages).
+func TestRequest_PersistFailureStillReturns200(t *testing.T) {
+	h, mlRepo, _, sender := newHandler(t)
+	mlRepo.failOn = "create"
+	rr := mountAndRequest(h, http.MethodPost, "/magic-link/request", `{"email":"bob@example.com"}`)
+	assert.Equal(t, http.StatusOK, rr.Code)
+	// No email was sent because no token was persisted.
+	assert.Empty(t, sender.messages)
+}
+
+// TestConsume_HappyPath_NewUser exercises sign-up-on-first-link.
+func TestConsume_HappyPath_NewUser(t *testing.T) {
+	h, mlRepo, svc, _ := newHandler(t)
+
+	// Seed one token by going through the request flow.
+	mountAndRequest(h, http.MethodPost, "/magic-link/request", `{"email":"alice@example.com"}`)
+	require.Len(t, mlRepo.tokens, 1)
+
+	// We need the plaintext to consume — derive it from the only token in the
+	// repo by reverse trick : the request handler doesn't expose it. So we
+	// drive consume with a fresh known-plaintext we put into the repo
+	// directly.
+	plain, hashHex, err := user.GenerateMagicLinkToken()
+	require.NoError(t, err)
+	mlRepo.tokens = map[string]*user.MagicLinkToken{
+		hashHex: {ID: 99, Email: "alice@example.com", TokenHash: hashHex, ExpiresAt: time.Now().Add(5 * time.Minute)},
+	}
+	mlRepo.nextID = 99
+
+	rr := mountAndRequest(h, http.MethodGet, "/magic-link/consume?token="+plain, "")
+	require.Equal(t, http.StatusOK, rr.Code, rr.Body.String())
+
+	var resp MagicLinkResponse
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &resp))
+	assert.Equal(t, "signed in", resp.Message)
+	assert.Equal(t, "jwt-for-user-alice@example.com", resp.Token)
+
+	// User was created.
+	require.Len(t, svc.createdUsers, 1)
+	assert.Equal(t, "alice@example.com", svc.createdUsers[0].Username)
+	assert.NotEmpty(t, svc.createdUsers[0].PasswordHash, "passwordless user must still have a non-empty hash (random unguessable value)")
+	assert.Equal(t, 1, svc.hashCalls)
+
+	// Token marked consumed.
+	for _, tok := range mlRepo.tokens {
+		require.NotNil(t, tok.ConsumedAt, "consumed_at must be set after consume")
+	}
+}
+
+// TestConsume_HappyPath_ExistingUser confirms no new user is created
+// when the email is already known.
+func TestConsume_HappyPath_ExistingUser(t *testing.T) {
+	h, mlRepo, svc, _ := newHandler(t)
+
+	// Pre-seed the user.
+	require.NoError(t, svc.CreateUser(context.Background(), &user.User{Username: "carol@example.com", PasswordHash: "x"}))
+	require.Len(t, svc.createdUsers, 1)
+	preCount := len(svc.createdUsers)
+
+	plain, hashHex, err := user.GenerateMagicLinkToken()
+	require.NoError(t, err)
+	mlRepo.tokens[hashHex] = &user.MagicLinkToken{ID: 1, Email: "carol@example.com", TokenHash: hashHex, ExpiresAt: time.Now().Add(5 * time.Minute)}
+
+	rr := mountAndRequest(h, http.MethodGet, "/magic-link/consume?token="+plain, "")
+	require.Equal(t, http.StatusOK, rr.Code, rr.Body.String())
+
+	// No new user.
+	assert.Len(t, svc.createdUsers, preCount)
+	assert.Equal(t, 0, svc.hashCalls, "no hash call when user exists")
+}
+
+// TestConsume_MissingToken returns 400.
+func TestConsume_MissingToken(t *testing.T) {
+	h, _, _, _ := newHandler(t)
+	rr := mountAndRequest(h, http.MethodGet, "/magic-link/consume", "")
+	assert.Equal(t, http.StatusBadRequest, rr.Code)
+}
+
+// TestConsume_UnknownToken returns 401 (single generic shape).
+func TestConsume_UnknownToken(t *testing.T) {
+	h, _, _, _ := newHandler(t)
+	rr := mountAndRequest(h, http.MethodGet, "/magic-link/consume?token=neverissued", "")
+	assert.Equal(t, http.StatusUnauthorized, rr.Code)
+}
+
+// TestConsume_ExpiredToken returns 401.
+func TestConsume_ExpiredToken(t *testing.T) {
+	h, mlRepo, _, _ := newHandler(t)
+	plain, hashHex, err := user.GenerateMagicLinkToken()
+	require.NoError(t, err)
+	mlRepo.tokens[hashHex] = &user.MagicLinkToken{
+		ID: 1, Email: "x@example.com", TokenHash: hashHex,
+		ExpiresAt: time.Now().Add(-1 * time.Minute), // already expired
+	}
+	rr := mountAndRequest(h, http.MethodGet, "/magic-link/consume?token="+plain, "")
+	assert.Equal(t, http.StatusUnauthorized, rr.Code)
+}
+
+// TestConsume_AlreadyConsumed returns 401 — single-use guarantee.
+func TestConsume_AlreadyConsumed(t *testing.T) {
+	h, mlRepo, _, _ := newHandler(t)
+	plain, hashHex, err := user.GenerateMagicLinkToken()
+	require.NoError(t, err)
+	now := time.Now()
+	mlRepo.tokens[hashHex] = &user.MagicLinkToken{
+		ID: 1, Email: "x@example.com", TokenHash: hashHex,
+		ExpiresAt: now.Add(5 * time.Minute), ConsumedAt: &now,
+	}
+	rr := mountAndRequest(h, http.MethodGet, "/magic-link/consume?token="+plain, "")
+	assert.Equal(t, http.StatusUnauthorized, rr.Code)
+}
+
+// TestBuildMagicLinkURL_TrailingSlash exercises the small helper.
+func TestBuildMagicLinkURL_TrailingSlash(t *testing.T) {
+	got := buildMagicLinkURL("http://x.local/", "abc")
+	assert.Equal(t, "http://x.local/api/v1/auth/magic-link/consume?token=abc", got)
+}

pkg/user/magic_link.go

@@ -0,0 +1,150 @@
+package user
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+	"gorm.io/gorm"
+)
+
+// MagicLinkToken is the persistent record of a passwordless-auth token.
+//
+// Per ADR-0028 Phase A: the token VALUE is never stored. Only its SHA-256
+// hash sits in the DB ; if the table leaks, the attacker has no usable
+// tokens (mirrors ADR-0021 secret retention via fingerprint approach).
+//
+// The plaintext token is delivered to the user exactly once via email and
+// must be supplied back through the consume endpoint to re-derive the
+// hash and find the row.
+type MagicLinkToken struct {
+	ID         uint       `gorm:"primaryKey"`
+	CreatedAt  time.Time  `gorm:"autoCreateTime;not null;index"`
+	Email      string     `gorm:"not null;index"`
+	TokenHash  string     `gorm:"not null;uniqueIndex;size:64"` // hex-encoded sha256 = 64 chars
+	ExpiresAt  time.Time  `gorm:"not null;index"`
+	ConsumedAt *time.Time `gorm:""`
+}
+
+// MagicLinkRepository is the persistence contract for magic-link tokens.
+// PostgresRepository implements it ; tests can use a fake.
+type MagicLinkRepository interface {
+	CreateMagicLinkToken(ctx context.Context, token *MagicLinkToken) error
+	GetMagicLinkTokenByHash(ctx context.Context, tokenHash string) (*MagicLinkToken, error)
+	MarkMagicLinkTokenConsumed(ctx context.Context, id uint, consumedAt time.Time) error
+	DeleteExpiredMagicLinkTokens(ctx context.Context, before time.Time) (int64, error)
+}
+
+// GenerateMagicLinkToken returns a fresh url-safe random token suitable
+// for inclusion in an email link, plus its SHA-256 hex digest for storage.
+//
+// The plaintext is what gets emailed ; the hash is what gets persisted.
+// 32 bytes of entropy = 256 bits ; collision-resistant for our scale.
+func GenerateMagicLinkToken() (plaintext, hashHex string, err error) {
+	buf := make([]byte, 32)
+	if _, err := rand.Read(buf); err != nil {
+		return "", "", fmt.Errorf("magic link rand: %w", err)
+	}
+	plaintext = base64.RawURLEncoding.EncodeToString(buf)
+	hashHex = HashMagicLinkToken(plaintext)
+	return plaintext, hashHex, nil
+}
+
+// HashMagicLinkToken returns the lowercase hex sha256 of token. Stable
+// over time : the same plaintext always maps to the same hash, so
+// consume can re-derive and look up the row.
+func HashMagicLinkToken(plaintext string) string {
+	sum := sha256.Sum256([]byte(plaintext))
+	return hex.EncodeToString(sum[:])
+}
+
+// CreateMagicLinkToken persists a magic-link token. The caller is
+// responsible for hashing the plaintext (cf. HashMagicLinkToken) and
+// setting ExpiresAt ; this method does not generate either.
+func (r *PostgresRepository) CreateMagicLinkToken(ctx context.Context, token *MagicLinkToken) error {
+	ctx, span := r.createSpan(ctx, "create_magic_link_token")
+	if span != nil {
+		defer span.End()
+		span.SetAttributes(attribute.String("email", token.Email))
+	}
+	if err := r.db.WithContext(ctx).Create(token).Error; err != nil {
+		if span != nil {
+			span.RecordError(err)
+		}
+		return fmt.Errorf("failed to create magic link token: %w", err)
+	}
+	return nil
+}
+
+// GetMagicLinkTokenByHash looks up a magic-link token by its hex sha256.
+// Returns (nil, nil) when no row matches — callers must treat that as
+// "invalid token" and respond with the same generic error as "expired"
+// or "consumed" to avoid leaking which condition failed.
+func (r *PostgresRepository) GetMagicLinkTokenByHash(ctx context.Context, tokenHash string) (*MagicLinkToken, error) {
+	ctx, span := r.createSpan(ctx, "get_magic_link_token_by_hash")
+	if span != nil {
+		defer span.End()
+	}
+	var t MagicLinkToken
+	err := r.db.WithContext(ctx).Where("token_hash = ?", tokenHash).First(&t).Error
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, nil
+		}
+		if span != nil {
+			span.RecordError(err)
+		}
+		return nil, fmt.Errorf("failed to get magic link token: %w", err)
+	}
+	return &t, nil
+}
+
+// MarkMagicLinkTokenConsumed sets consumed_at on the row with the given
+// ID. Idempotent only at the SQL-engine level — the consume handler is
+// responsible for refusing to act when consumed_at is already set.
+func (r *PostgresRepository) MarkMagicLinkTokenConsumed(ctx context.Context, id uint, consumedAt time.Time) error {
+	ctx, span := r.createSpan(ctx, "mark_magic_link_token_consumed")
+	if span != nil {
+		defer span.End()
+	}
+	res := r.db.WithContext(ctx).
+		Model(&MagicLinkToken{}).
+		Where("id = ?", id).
+		Update("consumed_at", consumedAt)
+	if res.Error != nil {
+		if span != nil {
+			span.RecordError(res.Error)
+		}
+		return fmt.Errorf("failed to mark magic link token consumed: %w", res.Error)
+	}
+	if res.RowsAffected == 0 {
+		return fmt.Errorf("no magic link token with id=%d", id)
+	}
+	return nil
+}
+
+// DeleteExpiredMagicLinkTokens removes rows whose expires_at is strictly
+// before the given cutoff. Returns the count deleted. Used by the
+// scheduled cleanup job.
+func (r *PostgresRepository) DeleteExpiredMagicLinkTokens(ctx context.Context, before time.Time) (int64, error) {
+	ctx, span := r.createSpan(ctx, "delete_expired_magic_link_tokens")
+	if span != nil {
+		defer span.End()
+	}
+	res := r.db.WithContext(ctx).
+		Where("expires_at < ?", before).
+		Delete(&MagicLinkToken{})
+	if res.Error != nil {
+		if span != nil {
+			span.RecordError(res.Error)
+		}
+		return 0, fmt.Errorf("failed to delete expired magic link tokens: %w", res.Error)
+	}
+	return res.RowsAffected, nil
+}

pkg/user/magic_link_cleanup.go

@@ -0,0 +1,56 @@
+package user
+
+import (
+	"context"
+	"time"
+
+	"github.com/rs/zerolog/log"
+)
+
+// MagicLinkCleanupRunner periodically deletes expired magic-link tokens
+// (ADR-0028 Phase A consequence — the rows accumulate without cleanup
+// otherwise, and stale rows are pure overhead since the token plaintext
+// is never stored).
+type MagicLinkCleanupRunner struct {
+	repo MagicLinkRepository
+}
+
+// NewMagicLinkCleanupRunner creates a new cleanup runner.
+func NewMagicLinkCleanupRunner(repo MagicLinkRepository) *MagicLinkCleanupRunner {
+	return &MagicLinkCleanupRunner{repo: repo}
+}
+
+// StartCleanupLoop runs the cleanup pass every `interval`. Stops when ctx
+// is cancelled. interval <= 0 disables the loop.
+func (r *MagicLinkCleanupRunner) StartCleanupLoop(ctx context.Context, interval time.Duration) {
+	if interval <= 0 {
+		return
+	}
+	go func() {
+		ticker := time.NewTicker(interval)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-ticker.C:
+				_, _ = r.runOnce(ctx)
+			}
+		}
+	}()
+}
+
+// runOnce performs a single cleanup pass. Returns the count of deleted rows.
+// Exposed for testing — tests drive runOnce directly instead of waiting on
+// the ticker.
+func (r *MagicLinkCleanupRunner) runOnce(ctx context.Context) (int64, error) {
+	n, err := r.repo.DeleteExpiredMagicLinkTokens(ctx, time.Now())
+	if err != nil {
+		log.Error().Ctx(ctx).Err(err).Msg("magic-link cleanup: delete failed")
+		return 0, err
+	}
+	if n > 0 {
+		log.Trace().Ctx(ctx).Int64("deleted", n).Msg("magic-link cleanup: removed expired tokens")
+	}
+	return n, nil
+}

pkg/user/magic_link_cleanup_test.go

@@ -0,0 +1,64 @@
+package user
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type fakeMLRepo struct {
+	deleteN    int64
+	deleteErr  error
+	cutoffSeen time.Time
+}
+
+func (r *fakeMLRepo) CreateMagicLinkToken(_ context.Context, _ *MagicLinkToken) error { return nil }
+func (r *fakeMLRepo) GetMagicLinkTokenByHash(_ context.Context, _ string) (*MagicLinkToken, error) {
+	return nil, nil
+}
+func (r *fakeMLRepo) MarkMagicLinkTokenConsumed(_ context.Context, _ uint, _ time.Time) error {
+	return nil
+}
+func (r *fakeMLRepo) DeleteExpiredMagicLinkTokens(_ context.Context, before time.Time) (int64, error) {
+	r.cutoffSeen = before
+	return r.deleteN, r.deleteErr
+}
+
+func TestRunOnce_ReturnsCount(t *testing.T) {
+	repo := &fakeMLRepo{deleteN: 7}
+	r := NewMagicLinkCleanupRunner(repo)
+	n, err := r.runOnce(context.Background())
+	require.NoError(t, err)
+	assert.EqualValues(t, 7, n)
+	assert.WithinDuration(t, time.Now(), repo.cutoffSeen, time.Second)
+}
+
+func TestRunOnce_PropagatesError(t *testing.T) {
+	repo := &fakeMLRepo{deleteErr: errors.New("simulated")}
+	r := NewMagicLinkCleanupRunner(repo)
+	_, err := r.runOnce(context.Background())
+	require.Error(t, err)
+}
+
+func TestStartCleanupLoop_StopsOnContextCancel(t *testing.T) {
+	repo := &fakeMLRepo{}
+	r := NewMagicLinkCleanupRunner(repo)
+	ctx, cancel := context.WithCancel(context.Background())
+	r.StartCleanupLoop(ctx, 10*time.Millisecond)
+	time.Sleep(25 * time.Millisecond) // 2 ticks
+	cancel()
+	time.Sleep(15 * time.Millisecond) // give the goroutine time to exit
+	// Implicit assertion: no goroutine leak (test would hang in -race mode otherwise).
+}
+
+func TestStartCleanupLoop_NoOpWhenIntervalZero(t *testing.T) {
+	repo := &fakeMLRepo{}
+	r := NewMagicLinkCleanupRunner(repo)
+	r.StartCleanupLoop(context.Background(), 0)
+	// Just make sure no goroutine is started ; nothing observable to assert
+	// beyond "no panic, returns immediately".
+}

pkg/user/magic_link_integration_test.go

@@ -0,0 +1,194 @@
+//go:build integration
+
+// Integration tests for the magic-link repository methods. Run with:
+//
+//	go test -tags integration ./pkg/user/...
+//
+// Requires a running Postgres reachable via the same env vars / defaults
+// the BDD suite already uses (DLC_DATABASE_HOST, etc., default
+// localhost:5432 from docker-compose).
+package user
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"testing"
+	"time"
+
+	"dance-lessons-coach/pkg/config"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// freshRepo connects to the local Postgres, creates a uniquely-named
+// schema for THIS test, and returns a repository scoped to it.
+// On test end, the schema is dropped (cleanup is best-effort).
+func freshRepo(t *testing.T) *PostgresRepository {
+	t.Helper()
+	cfg, err := config.LoadConfig()
+	require.NoError(t, err)
+
+	var raw [6]byte
+	_, err = rand.Read(raw[:])
+	require.NoError(t, err)
+	schema := "ml_test_" + hex.EncodeToString(raw[:])
+
+	// Bootstrap schema via a default-DSN repo (no search_path).
+	bootDSN := fmt.Sprintf(
+		"host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
+		cfg.GetDatabaseHost(),
+		cfg.GetDatabasePort(),
+		cfg.GetDatabaseUser(),
+		cfg.GetDatabasePassword(),
+		cfg.GetDatabaseName(),
+		cfg.GetDatabaseSSLMode(),
+	)
+	bootRepo, err := NewPostgresRepositoryFromDSN(cfg, bootDSN)
+	require.NoError(t, err)
+	require.NoError(t, bootRepo.Exec(fmt.Sprintf(`CREATE SCHEMA "%s"`, schema)))
+
+	t.Cleanup(func() {
+		_ = bootRepo.Exec(fmt.Sprintf(`DROP SCHEMA "%s" CASCADE`, schema))
+	})
+
+	dsn := BuildSchemaIsolatedDSN(cfg, schema)
+	repo, err := NewPostgresRepositoryFromDSN(cfg, dsn)
+	require.NoError(t, err)
+	return repo
+}
+
+// TestMagicLinkRepo_CreateAndGetByHash is the end-to-end happy path :
+// store a token, look it up by hash, get the row back.
+func TestMagicLinkRepo_CreateAndGetByHash(t *testing.T) {
+	repo := freshRepo(t)
+	ctx := context.Background()
+
+	plain, hashHex, err := GenerateMagicLinkToken()
+	require.NoError(t, err)
+
+	tok := &MagicLinkToken{
+		Email:     "alice@example.com",
+		TokenHash: hashHex,
+		ExpiresAt: time.Now().Add(15 * time.Minute),
+	}
+	require.NoError(t, repo.CreateMagicLinkToken(ctx, tok))
+	assert.NotZero(t, tok.ID, "ID should be populated by GORM after Create")
+
+	got, err := repo.GetMagicLinkTokenByHash(ctx, hashHex)
+	require.NoError(t, err)
+	require.NotNil(t, got, "fresh token must be retrievable")
+	assert.Equal(t, "alice@example.com", got.Email)
+	assert.Nil(t, got.ConsumedAt, "fresh token is not yet consumed")
+
+	// Lookup by the plaintext (which the consume handler does NOT receive
+	// directly — it must hash first). This confirms the hashing direction
+	// is consistent.
+	got2, err := repo.GetMagicLinkTokenByHash(ctx, HashMagicLinkToken(plain))
+	require.NoError(t, err)
+	require.NotNil(t, got2)
+	assert.Equal(t, tok.ID, got2.ID)
+}
+
+// TestMagicLinkRepo_GetByHash_Missing returns (nil, nil) for a hash that
+// never existed. Callers must NOT distinguish "missing" from "expired"
+// or "consumed" — they all collapse to a single generic error to the user.
+func TestMagicLinkRepo_GetByHash_Missing(t *testing.T) {
+	repo := freshRepo(t)
+	got, err := repo.GetMagicLinkTokenByHash(context.Background(), HashMagicLinkToken("never-issued"))
+	require.NoError(t, err)
+	assert.Nil(t, got)
+}
+
+// TestMagicLinkRepo_MarkConsumed flips consumed_at and refuses to act
+// on a non-existent ID.
+func TestMagicLinkRepo_MarkConsumed(t *testing.T) {
+	repo := freshRepo(t)
+	ctx := context.Background()
+
+	_, hashHex, err := GenerateMagicLinkToken()
+	require.NoError(t, err)
+	tok := &MagicLinkToken{
+		Email:     "bob@example.com",
+		TokenHash: hashHex,
+		ExpiresAt: time.Now().Add(15 * time.Minute),
+	}
+	require.NoError(t, repo.CreateMagicLinkToken(ctx, tok))
+
+	now := time.Now().UTC().Truncate(time.Second)
+	require.NoError(t, repo.MarkMagicLinkTokenConsumed(ctx, tok.ID, now))
+
+	got, err := repo.GetMagicLinkTokenByHash(ctx, hashHex)
+	require.NoError(t, err)
+	require.NotNil(t, got)
+	require.NotNil(t, got.ConsumedAt, "consumed_at must be set")
+	assert.WithinDuration(t, now, got.ConsumedAt.UTC(), time.Second)
+
+	// Marking a non-existent ID returns an error (defensive — the consume
+	// handler should never call us with a fake ID, but if it does we want
+	// the failure to be loud).
+	err = repo.MarkMagicLinkTokenConsumed(ctx, 999999, time.Now())
+	require.Error(t, err)
+}
+
+// TestMagicLinkRepo_DeleteExpired confirms the cleanup pass deletes
+// strictly-before-cutoff rows and leaves future ones alone.
+func TestMagicLinkRepo_DeleteExpired(t *testing.T) {
+	repo := freshRepo(t)
+	ctx := context.Background()
+
+	now := time.Now()
+	expired := &MagicLinkToken{
+		Email:     "expired@example.com",
+		TokenHash: HashMagicLinkToken("expired-token"),
+		ExpiresAt: now.Add(-1 * time.Hour),
+	}
+	fresh := &MagicLinkToken{
+		Email:     "fresh@example.com",
+		TokenHash: HashMagicLinkToken("fresh-token"),
+		ExpiresAt: now.Add(1 * time.Hour),
+	}
+	require.NoError(t, repo.CreateMagicLinkToken(ctx, expired))
+	require.NoError(t, repo.CreateMagicLinkToken(ctx, fresh))
+
+	deleted, err := repo.DeleteExpiredMagicLinkTokens(ctx, now)
+	require.NoError(t, err)
+	assert.EqualValues(t, 1, deleted, "exactly one row was past the cutoff")
+
+	// Expired row is gone, fresh row is still there.
+	got, err := repo.GetMagicLinkTokenByHash(ctx, HashMagicLinkToken("expired-token"))
+	require.NoError(t, err)
+	assert.Nil(t, got, "expired token must be gone")
+
+	got, err = repo.GetMagicLinkTokenByHash(ctx, HashMagicLinkToken("fresh-token"))
+	require.NoError(t, err)
+	require.NotNil(t, got, "fresh token must remain")
+}
+
+// TestMagicLinkRepo_HashUniqueness is a defensive check that the unique
+// index on token_hash actually rejects duplicates. If the index is ever
+// dropped from the schema, this test catches it before security does.
+func TestMagicLinkRepo_HashUniqueness(t *testing.T) {
+	repo := freshRepo(t)
+	ctx := context.Background()
+
+	_, hashHex, err := GenerateMagicLinkToken()
+	require.NoError(t, err)
+
+	first := &MagicLinkToken{
+		Email:     "a@example.com",
+		TokenHash: hashHex,
+		ExpiresAt: time.Now().Add(15 * time.Minute),
+	}
+	require.NoError(t, repo.CreateMagicLinkToken(ctx, first))
+
+	dup := &MagicLinkToken{
+		Email:     "b@example.com",
+		TokenHash: hashHex, // same hash as `first`
+		ExpiresAt: time.Now().Add(15 * time.Minute),
+	}
+	err = repo.CreateMagicLinkToken(ctx, dup)
+	require.Error(t, err, "second insert with same hash must violate the unique index")
+}

pkg/user/magic_link_test.go

@@ -0,0 +1,78 @@
+package user
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/hex"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestGenerateMagicLinkToken_ShapeAndHashAgree confirms the contract that
+// HashMagicLinkToken(plaintext) == returned hashHex. Without that, the
+// consume handler can never look up what request stored.
+func TestGenerateMagicLinkToken_ShapeAndHashAgree(t *testing.T) {
+	plain, hashHex, err := GenerateMagicLinkToken()
+	require.NoError(t, err)
+
+	assert.NotEmpty(t, plain)
+	assert.NotEmpty(t, hashHex)
+	assert.Len(t, hashHex, 64, "sha256 hex = 64 chars")
+	assert.Equal(t, hashHex, HashMagicLinkToken(plain),
+		"GenerateMagicLinkToken must return a hash that matches HashMagicLinkToken(plain)")
+}
+
+// TestGenerateMagicLinkToken_PlainIsURLSafeBase64 confirms the link can
+// be embedded in a URL without further escaping. RawURLEncoding => no
+// "/", "+", or "=" padding chars.
+func TestGenerateMagicLinkToken_PlainIsURLSafeBase64(t *testing.T) {
+	plain, _, err := GenerateMagicLinkToken()
+	require.NoError(t, err)
+
+	for _, bad := range []string{"/", "+", "="} {
+		assert.False(t, strings.Contains(plain, bad),
+			"plaintext token must not contain %q (URL-unsafe)", bad)
+	}
+
+	decoded, err := base64.RawURLEncoding.DecodeString(plain)
+	require.NoError(t, err, "plaintext must round-trip through RawURLEncoding")
+	assert.Len(t, decoded, 32, "32 bytes of entropy")
+}
+
+// TestGenerateMagicLinkToken_Unique confirms two consecutive calls
+// produce different tokens (not a deterministic seeding bug).
+func TestGenerateMagicLinkToken_Unique(t *testing.T) {
+	a, ah, err := GenerateMagicLinkToken()
+	require.NoError(t, err)
+	b, bh, err := GenerateMagicLinkToken()
+	require.NoError(t, err)
+
+	assert.NotEqual(t, a, b, "plaintexts must differ between calls")
+	assert.NotEqual(t, ah, bh, "hashes must differ between calls")
+}
+
+// TestHashMagicLinkToken_StableAndCorrect confirms HashMagicLinkToken is
+// a pure function (same input -> same output) AND that it produces the
+// expected sha256 hex digest. Cross-checked against the stdlib so we
+// catch any accidental algorithm swap.
+func TestHashMagicLinkToken_StableAndCorrect(t *testing.T) {
+	const sample = "abc123-test-token"
+	got1 := HashMagicLinkToken(sample)
+	got2 := HashMagicLinkToken(sample)
+	assert.Equal(t, got1, got2, "HashMagicLinkToken must be deterministic")
+
+	sum := sha256.Sum256([]byte(sample))
+	want := hex.EncodeToString(sum[:])
+	assert.Equal(t, want, got1, "HashMagicLinkToken must be sha256 hex")
+}
+
+// TestHashMagicLinkToken_DiffersOnDifferentInput is the tautological
+// counter-test of stability : different inputs -> different outputs.
+// Catches the (unlikely) case where someone replaces the impl with
+// a constant.
+func TestHashMagicLinkToken_DiffersOnDifferentInput(t *testing.T) {
+	assert.NotEqual(t, HashMagicLinkToken("a"), HashMagicLinkToken("b"))
+}

pkg/user/postgres_repository.go

@@ -160,7 +160,7 @@ func NewPostgresRepositoryFromDSN(cfg *config.Config, dsn string) (*PostgresRepo
 	sqlDB.SetMaxIdleConns(cfg.GetDatabaseMaxIdleConns())
 	sqlDB.SetConnMaxLifetime(cfg.GetDatabaseConnMaxLifetime())
 
-	if err := db.AutoMigrate(&User{}); err != nil {
+	if err := db.AutoMigrate(&User{}, &MagicLinkToken{}); err != nil {
 		return nil, fmt.Errorf("failed to auto-migrate via custom DSN: %w", err)
 	}
 
@@ -264,8 +264,8 @@ func (r *PostgresRepository) initializeDatabase() error {
 	sqlDB.SetMaxIdleConns(r.config.GetDatabaseMaxIdleConns())
 	sqlDB.SetConnMaxLifetime(r.config.GetDatabaseConnMaxLifetime())
 
-	// Auto-migrate the User model
-	if err := r.db.AutoMigrate(&User{}); err != nil {
+	// Auto-migrate the User model + MagicLinkToken (ADR-0028 Phase A)
+	if err := r.db.AutoMigrate(&User{}, &MagicLinkToken{}); err != nil {
 		return fmt.Errorf("failed to auto-migrate: %w", err)
 	}