Load config, harden processing and notifications

- Actually load configs/config.yaml at startup (init_config was commented out)
- Add timeouts and error handling to all HTTP calls; run blocking requests
  in threads; serialize processing with a lock; run initial check in background
- URL-encode Telegram messages and HTML-escape scraped data
- Fix GPV crash on empty schedule, 00:00 end time, date sorting and fallback format
- Parse PO table per row; fix daily reminder check and change detection
- Use per-instance timestamps in dataclasses; robust config value parsing
- Matrix: use v3 PUT send endpoint; strip secrets from logged errors
- Resolve templates/static/test paths relative to the project; use lifespan
- Move debug GPV data to test/data_gpv.json; add CLAUDE.md

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -1 +1,4 @@
 /configs/secrets.yaml
+__pycache__/
+.idea/
+.venv/