New modules: - tesseract_vocab_extractor.py: Bounding-box OCR with multi-PSM pipeline - grid_detection_service.py: CV-based grid/table detection for worksheets - vocab_session_store.py: PostgreSQL persistence for vocab sessions - trocr_api.py: TrOCR handwriting recognition endpoint - dsfa_rag_api.py + dsfa_corpus_ingestion.py: DSFA RAG corpus search Changes: - Dockerfile: Install tesseract-ocr + deu/eng language packs - requirements.txt: Add PyMuPDF, pytesseract, Pillow - main.py: Register new routers, init DB pools + Qdrant collections Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>