feat(governance): align project metadata triad with native GitHub Projects v2 fields

[nicolasvd]

Closes #1

📌 Summary

Branch: feat/issue-1-native-project-metadata → main
Type: feat(governance)
Related Issue: #1 feat(governance): align project metadata triad with native GitHub Projects v2 fields

• Deprecated legacy custom metadata triad (Business Value ⭐, Tech Complexity 🧩, Severity 🚨) across the entire repository.
• Standardized metadata to 100% native GitHub Projects v2 fields: Priority (P0, P1, P2), Size (XS, S, M, L, XL), Estimate (numeric points/days), and Status (Backlog → Ready → In progress → In review → Done).
• Re-anchored Rule 0.1 Epic Gating to Size: L / XL with zero branch guardrail and DAG decomposition.
• Formalized Rule A append-only audit trail for project board item adjustments via comments.
• Updated sidecar sync-issue-progress.mjs for case-resilient status matching and configured kernel.config.json for Project 2 (Agentic Delivery Board).

---

📂 Affected Files

File	Diff	Role
kernel.config.json	+2 -2	Enabled GitHub project tracking on Project 2
AGENTS.md & agent.md	+8 -8	Updated Persona delegation matrix, invariants, and native metadata
ARCHITECTURE.md	+1 -1	Updated Rule 0.1 Epic Gating invariant (Size: L / XL)
.agent/personas/p1-product-planner.md	+4 -3	P1 ownership: Priority, Milestone, Estimate
.agent/personas/p4-system-architect.md	+10 -8	P4 ownership: Size (XS..XL), Estimate, Epic Gating
.agent/rules/backlog-planner.md	+17 -19	Native schema table, Rule 0.1, Rule A, Kanban machine
.agent/rules/agent-lifecycle.md	+1 -1	P4 blueprint deliverable updated to Size & Estimate
.agent/templates/4-pillar-spec.md	+5 -5	Metadata summary, Pillar 3 Size/Estimate, Dual-Write YAML block
.agent/templates/epic-spec.md	+3 -2	Priority, Size, Estimate headers
.agent/templates/crashlytics-triage-issue.md	+2 -2	Severity replaced by native Priority (P0, P1, P2)
.github/ISSUE_TEMPLATE/crashlytics_triage.yml	+5 -6	Dropdown updated to Priority (P0, P1, P2)
.agent/skills/plan-issue/SKILL.md	+9 -8	Steps 3 & 4.1 aligned with native metadata & Epic routing
.agent/skills/triage-feedback/SKILL.md	+4 -4	Triage table mapped to Priority (P0, P1, P2)
.agent/sidecars/sync-issue-progress.mjs	+2 -2	Case-resilient status matching for In progress

---

✅ Quality Airbag — ./scripts/quality-check.sh

Check	Result
Kotlin / Java compilation	✅ 0 errors
Android Lint (debug)	✅ 0 warnings
Android Lint (release)	✅ 0 warnings
Unit tests	✅ Passed · 0 failed
Robolectric UI tests	✅ Passed · 0 failed
Firestore security rules	✅ Passed · 0 failed
./scripts/validate-docs.sh	✅ 11/11 categories valid (all byte budgets strictly respected)

---

⚡ FinOps & Agent Efficiency

Metric	Measurement	Status
Conversation turns	3 turns	✅ Optimal (< 20)
Circuit Breaker	0 trip (max 3 iterations)	✅ Passed · No loop
Context Hygiene	Clean delegation & execution	✅ Compliant
Design Drift Check	Core contracts & tokens preserved	✅ Compliant

---

📸 UI Snapshots / Roborazzi Visual Diffs

N/A — No visual/UI changes (Governance, configuration, rules, templates, and sidecars only).

---

Caution

Zero Auto-Merge — Explicit approval required.
This PR will NOT be merged until the author explicitly confirms: "Tu peux merger" or equivalent.
P6 presents this PR link and stops. Merge is a deliberate human action.