- PDF: extracts selectable text via pymupdf, falls back to Tesseract OCR for scanned docs
- PDF: renders first page as screenshot thumbnail
- Images: Tesseract OCR for text extraction, OpenAI vision API fallback for photos
- Plain text files: direct decode
- All extracted text stored in extracted_text field for search/embedding
- Tested: PDF upload → text extracted → AI classified → searchable
New deps: pymupdf, pytesseract, Pillow
System dep: tesseract-ocr added to both Dockerfiles
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
