docs: remove VERTEX_API_KEY references from config/docs

docs(readme): replace minimal architecture diagram with comprehensive version

docs: comprehensive English README

docs: Sprint Fix 5 — sync README, CLAUDE.md, add conftest.py

rename: Scriptorium AI → IIIF Studio across entire codebase

fix(hf): colorTo gold → yellow (valeurs HF : red yellow green blue indigo purple pink gray)

feat(sprint5-session-a): Dockerisation + configuration HuggingFace Spaces

Initial commit