docs(vibe): bootstrap vibe/ knowledge tree + ecosystem AGENTS.md

Add a root AGENTS.md (ecosystem map of factory/tools/cms + agent operating
rules + the persona cohort & workflow) and a new vibe/ knowledge base for LLM
agents, modeled on tree-docs conventions and the factory house style.

vibe/ folders (each with a README hub + contribution rules):
- ADR/      optimized MADR-lite; canonical home going forward (doc/adr stays historical)
- PRD/      one subfolder per PRD, mandatory STATUS.md, QA strategy for big ones
- investigations/  single INV-NNN-slug.md, or stub + folder w/ notebooks
- guidebooks/      tree-docs maps; lab-ecosystem guidebook of factory+tools+cms
- runbooks/        [AGENT]/[HUMAN] step procedures (EN; doc/runbooks stays FR)
- shareouts/       dated FR handouts (decks/mp4)

Seed content (first ADR + PRD): a safe, production-like environment to rehearse
risky changes and recovery without touching real prod — local-only sandbox
(k3d + arm64 VMs) with a hard prod/sandbox isolation boundary. Includes
INV-001 (prod blast-radius couplings), the ecosystem guidebook, and a FR shareout.

Conventions enforced: no-tombstone rule, breadcrumb spine, bidirectional
cross-links, theme:base mermaid (MCP-validated) + ordered-list-after-diagram.
Built with a Workflow + persona cohort; 24 files, zero dead links.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

vibe/shareouts/README.md

@@ -0,0 +1,56 @@
+[vibe](../README.md) > **Shareouts**
+
+# Shareouts
+
+> **Status:** Active
+> **Last Updated:** 2026-06-23
+> **Related:** [vibe guidebooks](../guidebooks/README.md) · [vibe runbooks](../runbooks/README.md)
+
+## What a shareout is
+
+A **shareout** captures something substantial that was **done or seriously considered** — the outcome of an ADR, a PRD, or an investigation — and packages it as a **human-facing handout** you can hand to a person to explain what happened and why it matters.
+
+Where guidebooks are the standing reference map and runbooks are the procedures, a shareout is a moment-in-time communication artifact: "here is the thing we built / decided / explored, told for humans."
+
+```mermaid
+%%{init: {'theme': 'base'}}%%
+flowchart LR
+    classDef src fill:#2563eb,stroke:#1e40af,color:#fff
+    classDef proc fill:#059669,stroke:#047857,color:#fff
+    classDef store fill:#7c3aed,stroke:#6d28d9,color:#fff
+    WORK["Substantial work<br>(ADR / PRD / investigation)"]:::src --> SO["Shareout<br>(dated handout folder)"]:::proc --> HUM["Humans<br>(read .md, deck, watch .mp4)"]:::store
+```
+
+1. Some substantial work lands — an ADR is decided, a PRD phase ships, an investigation concludes.
+2. It is packaged into a dated shareout folder holding the human-facing handouts.
+3. Humans consume the handout: a Markdown summary, a slide deck, and optionally a narrated video.
+
+## Convention: one dated subfolder per shareout
+
+> [!IMPORTANT]
+> Each shareout lives in **its own dated subfolder** named `YYYY-MM-DD-slug/`. The folder holds the human-facing handouts for that shareout: `.md` summaries, decks, and an optional `.mp4`.
+
+The handouts inside a shareout folder can include:
+
+- **`.md` summaries** — the written walkthrough (the folder's `README.md` is the front door).
+- **Decks** — slides for presenting the work.
+- **Optional `.mp4`** — `ffmpeg` compilations of screenshots, [Playwright](../../ansible/arcodange/factory/README.md) captures, or a narrated explainer produced with the `documentary-video` skill.
+
+> [!NOTE]
+> **Handouts are written in FRENCH.** The audience is humans, and the lab's human-facing audience is French-speaking. (This is the deliberate exception to the otherwise-English `vibe/` tree, which exists for LLM agents.)
+
+## Index
+
+| Shareout | What it covers | Status |
+|---|---|---|
+| [2026-06-23 · Vibe & safe-env](2026-06-23-vibe-and-safe-env/README.md) | Mise en place du tronc `vibe/` (guidebooks, runbooks, shareouts) et le PRD de l'environnement « safe prod-like » | ✅ Active |
+
+## Rules to contribute
+
+1. **One dated folder per shareout** — `YYYY-MM-DD-slug/`, kebab-case slug, ISO date. Never dump loose files at this level.
+2. **Folder `README.md` is the front door** — it carries the breadcrumb, a TL;DR, and links to every handout in the folder (deck, video, sub-summaries).
+3. **Handouts in French** — the audience is human. (Reminder: the rest of `vibe/` is English for agents.)
+4. **Add an index row here** for every new shareout, with a one-line French summary and status, newest at the top.
+5. **Use the `tree-docs` skill** for the breadcrumb spine and the per-folder README hub; use the `documentary-video` skill when a shareout warrants a narrated `.mp4`.
+6. **Bidirectional links** — if a shareout points to an ADR/PRD/guidebook, link back from there. Descriptive link text only.
+7. **Status legend.** ✅ done · 🟡 beta · 🔴 critical · ⚠️ known issue · ❌ disabled · ⬜ not started.