chore: finir le retrait execution_mode (audit du commit precedent)

chore(versioning): reposition project as 0.9.0 (pre-1.0)

docs(operations): remove sprint narrative (Phase 2 L2)

docs(root): move ACCESSIBILITY and SPECS out of root to their proper sections

docs(archive): consolidate audits, migration, pre-v2 roadmap under docs/archive/

feat(sprint-S6)!: déploiement institutionnel — pin Tesseract, CSRF strict, logs JSON, observability

docs(sprint-H.9): archive migration plans + cleanup stale doc paths

docs: refonte Diataxis + 8 documents institutionnels (S60)

feat(sprint-A11): doc institutionnelle (déploiement + RGPD + traduction EN)

feat(sprint-A9): release pipeline PyPI + ghcr.io + GitHub Release