Improve photo extraction robustness and add logging ...

- Add _extract_photos() helper to handle both list and dict formats
- _build_photo_urls() now skips non-dict entries gracefully
- Fallback to detail.main_photo when no photos array is present
- Add photos_count to payload for easy verification
- Add crawler warning log when a listing has zero photos after normalization
- Prefer detail photos (usually higher quality), fallback to catalog

Co-Authored-By: Claude <noreply@anthropic.com>

Implement MVP DOM.RIA parser with curl_cffi scraping ...

- Add src/ modules: config, session, parser, normalizer, collector, storage, crawler, main
- Implement curl_cffi session with chrome124 impersonation and cookie warmup
- Extract __INITIAL_STATE__ using bracket-counting JSON parser
- Normalize DOM.RIA data into data_collector payload format
- Add SQLite resume storage for deduplication
- Implement rate limiting: 10s between pages/details, 2min pause every 50 pages
- Add CLI entry point with argparse for city/category/operation selection
- Add Dockerfile and requirements.txt
- Update TECH_SPEC.md with v3.0 post-MVP status and empirical data findings
- Update README.md with usage instructions

Co-Authored-By: Claude <noreply@anthropic.com>