- Add PDF preview support using pdf2image
- Enable bounding box overlay visualization for PDFs
- Implement database persistence with SQLModel (Invoice, LineItem)
- Add InvoiceRepository with save and duplicate detection
- Improve DB status messages (show 'unavailable' once at startup)
- Show 'Demo Mode' toast only once per session
- Fix torch.load and transformers deprecation warnings
- Add conda environment.yml for reproducible setup
- Update README with conda installation instructions
