- Fixed critical API synchronization bug: send Unix timestamp as long integer instead of ISO datetime string
- Updated _get_last_fixture_timestamp() to return str(fixture_active_time) for proper server compatibility
- Added comprehensive fixtures management system with dashboard integration
- Created fixtures list and detail pages with Bootstrap styling and admin controls
- Enhanced API client with proper timestamp handling and authentication for ZIP downloads
- Updated documentation (README.md, CHANGELOG.md, DOCUMENTATION.md) with new features
- Completed fixtures dashboard with real-time synchronization and administrative controls
- Fixed server communication to use proper Unix timestamp format: '1755773200' instead of '2025-08-21T14:31:3'