Phase 2c — testing infrastructure (43 tests, CI gating, docker-compose)

Brings the project to a TDD/BDD-friendly state — apologies for shipping
Phase 1.5 + Phase 2 code-first, that violated feedback_tdd_first_bdd_required.

What's added :

- helpers_test.go : FakeTelegram (httptest server that records sendMessage /
  deleteMessage / setWebhook / etc.), miniredis bootstrap, MakeUpdate /
  PostWebhook helpers. The same harness simulates 'a user DMing the bot'
  end-to-end without hitting Telegram cloud — answer to the user question.
- 43 tests covering : allowlist parsing, telegram type helpers (UserID /
  ChatID / Text / messageID), secret_token constant-time compare, Backoff
  schedule, Auth (login wrong/right/logout/TTL/nil-receiver), EchoHandler,
  HTTPHandler (forward / timeout / non-2xx / empty body), AuthHandler
  (start / auth / whoami / logout / replay defense delete), Server (bad
  secret 401, unknown bot 404, allowlist drop, gated bot prompt,
  full /auth → echo → /logout flow, healthz/readyz).
- All tests pass with -race in 1.6s, no external deps (miniredis +
  httptest in-process).

Infra :

- Updated .gitea/workflows/dockerimage.yaml : new 'test' job
  (go vet + go test -race) gates the build-and-push-image job. CI now
  also runs on pull_request.
- docker-compose.yml : redis + postgres for full local stack.
- Makefile : test-race, compose-up/down targets.
- README updated with test + local-dev sections.

Refs ~/.claude/plans/pour-les-notifications-on-inherited-seal.md § Phase 2.

telegram_types_test.go

@@ -0,0 +1,67 @@
+package main
+
+import "testing"
+
+func TestUpdate_ChatID(t *testing.T) {
+	u := MakeUpdate(1, 100, 42, 7, "hi")
+	id, ok := u.ChatID()
+	if !ok || id != 42 {
+		t.Fatalf("Message chat = %d/%v", id, ok)
+	}
+
+	editU := Update{EditedMessage: &Message{Chat: Chat{ID: 99}}}
+	id, ok = editU.ChatID()
+	if !ok || id != 99 {
+		t.Fatalf("EditedMessage chat = %d/%v", id, ok)
+	}
+
+	cb := Update{CallbackQuery: &CallbackQuery{Message: &Message{Chat: Chat{ID: 77}}}}
+	id, ok = cb.ChatID()
+	if !ok || id != 77 {
+		t.Fatalf("CallbackQuery chat = %d/%v", id, ok)
+	}
+
+	empty := Update{}
+	if _, ok := empty.ChatID(); ok {
+		t.Fatal("empty Update must have no chat")
+	}
+}
+
+func TestUpdate_UserID(t *testing.T) {
+	u := MakeUpdate(1, 7497777082, 42, 7, "hi")
+	id, ok := u.UserID()
+	if !ok || id != 7497777082 {
+		t.Fatalf("Message from = %d/%v", id, ok)
+	}
+
+	cb := Update{CallbackQuery: &CallbackQuery{From: &User{ID: 555}}}
+	id, ok = cb.UserID()
+	if !ok || id != 555 {
+		t.Fatalf("CallbackQuery from = %d/%v", id, ok)
+	}
+
+	noFrom := Update{Message: &Message{Chat: Chat{ID: 1}}}
+	if _, ok := noFrom.UserID(); ok {
+		t.Fatal("Message without From should have no UserID")
+	}
+}
+
+func TestUpdate_Text(t *testing.T) {
+	if got := MakeUpdate(1, 1, 1, 1, "hi").Text(); got != "hi" {
+		t.Errorf("Message text: %q", got)
+	}
+	cb := Update{CallbackQuery: &CallbackQuery{Data: "btn:42"}}
+	if got := cb.Text(); got != "btn:42" {
+		t.Errorf("CallbackQuery data: %q", got)
+	}
+}
+
+func TestMessageID(t *testing.T) {
+	u := MakeUpdate(1, 1, 1, 88, "x")
+	if got := messageID(u); got != 88 {
+		t.Errorf("messageID = %d", got)
+	}
+	if got := messageID(Update{}); got != 0 {
+		t.Errorf("empty Update messageID = %d (want 0)", got)
+	}
+}