fix: comprehensive repo audit — 15 issues fixed

fix(ci): match HuggingFace Space name case (IIIF-Studio, not iiif-studio)

rename: Scriptorium AI → IIIF Studio across entire codebase

fix(ci): add workflow_call trigger to tests.yml (required for reusable workflow)

feat(ci): tests CI + deploy bloqué sur tests verts

fix: root redirect /docs + Node.js 24 dans la CI

fix(ci): remplacer action inexistante par git push direct vers HF

ci: GitHub Action déploiement automatique HuggingFace Spaces