fix(security): Sprint 1 — path traversal, SSRF, Docker hardening, error exposure

feat(ingest): IIIF-native Sprint 2 — detect IIIF Image Service at ingestion

fix: page IDs with trailing dots, Reader profile handling, Editor 404 UX

fix(backend): Sprint Fix 2 — data integrity, error handling, robustness

rename: Scriptorium AI → IIIF Studio across entire codebase

fix(sprint-f2): fiabilité — error handling, async I/O, pagination, cache, prompts

fix(sprint-f1): sécurité — path traversal, SSRF, CORS, validation inputs

fix: 3 production bugs — mistralai import, page ID collision, provider logging

fix(ingest): add User-Agent and headers to httpx requests to fix Gallica 403

feat(sprint4-session-b): endpoints jobs, ingestion et modèles IA