OCR (v0.1.85): new codai/ocr/ subsystem — dedicated OCR engines (NOT a VLM):
- docTR (in-process, GPU) + PaddleOCR & Surya (isolated-venv subprocess workers
  via codai/ocr/workers/ocr_worker.py to avoid opencv-contrib/pillow<11 clashes;
  paddle-gpu bundles its own CUDA so a cu12x wheel runs on newer-CUDA hosts).
- /v1/ocr, /v1/ocr/batch, /v1/ocr/schemas CRUD; `ocr` pipeline step.
- Data-driven, user-extensible extraction schemas (named files + inline + auto),
  built-in seeds (italian_sentenza/generic_document/invoice); optional JSON Schema
  validation. Structured extraction via an existing coderai text model.
- Configurable stamp/signature detection (off|layout|detector|both); bundled
  signature YOLO default; layout markers EN+IT (timbro/sigillo/firma).
- Admin OCR card: engines/instances/detect/extraction + schema picker/raw-JSON/
  field-builder + isolated-venv build trigger (background build + status).
- Isolated venvs resolve baked(/o...