docs(index): repair broken links + lock against drift

test(7.D): supprime tests intégration legacy + tutorial obsolète

feat(migration): Lot A — core.{modules,facts} → domain/, suppression des shims

feat(migration): Phase 5.C batch 7 — pré-requis + 2 derniers renderers

docs: refonte Diataxis + 8 documents institutionnels (S60)