fix: comprehensive repo audit — 15 issues fixed

fix(frontend): Sprint 2b — dead code, accessibility, Viewer robustness, ApiError

fix: "error [object Object]" on API validation errors + SQLite migration

refactor: use API-reported supports_vision instead of hardcoded model names

feat(schemas): IIIF-native Sprint 1 — schema evolution for streaming architecture

fix(frontend): Sprint Fix 3 — type safety, memory leaks, error handling

rename: Scriptorium AI → IIIF Studio across entire codebase

fix(sprint-f4-f5): tests faux-positifs, frontend bugs, Dockerfile unique

fix(api): guard catch-all against /api/* paths in production + refactor Admin UI

feat: multi-provider dynamique — ajout Mistral/Pixtral, détection auto des providers

feat: supprimer la saisie de clé API dans l'UI — les clés viennent des secrets HF

feat(sprint6-B): validation éditoriale + recherche plein texte

feat(frontend): interface d'administration — Sprint 6 Session A

feat(sprint5): frontend React minimal — visionneuse + 4 couches