This commit addresses multiple issues with schedule management and updates
documentation to reflect the transition from YAML-based to database-backed
configuration system.
**Documentation Updates:**
- Update DEPLOYMENT.md to remove all references to YAML config files
- Document that all configurations are now stored in SQLite database
- Update API examples to use config IDs instead of YAML filenames
- Remove configs directory from backup/restore procedures
- Update volume management section to reflect database-only storage
**Cron Expression Handling:**
- Add comprehensive documentation for APScheduler cron format conversion
- Document that from_crontab() accepts standard format (Sunday=0) and converts automatically
- Add validate_cron_expression() helper method with detailed error messages
- Include helpful hints for day-of-week field errors in validation
- Fix all deprecated datetime.utcnow() calls, replace with datetime.now(timezone.utc)
**Timezone-Aware DateTime Fixes:**
- Fix "can't subtract offset-naive and offset-aware datetimes" error
- Add timezone awareness to croniter.get_next() return values
- Make _get_relative_time() defensive to handle both naive and aware datetimes
- Ensure all datetime comparisons use timezone-aware objects
**Schedule Edit UI Fixes:**
- Fix JavaScript error "Cannot set properties of null (setting 'value')"
- Change reference from non-existent 'config-id' to correct 'config-file' element
- Add config_name field to schedule API responses for better UX
- Eagerly load Schedule.config relationship using joinedload()
- Fix AttributeError: use schedule.config.title instead of .name
- Display config title and ID in schedule edit form
**Technical Details:**
- app/web/services/schedule_service.py: 6 datetime.utcnow() fixes, validation enhancements
- app/web/services/scheduler_service.py: Documentation, validation, timezone fixes
- app/web/templates/schedule_edit.html: JavaScript element reference fix
- docs/DEPLOYMENT.md: Complete rewrite of config management sections
Fixes scheduling for Sunday at midnight (cron: 0 0 * * 0)
Fixes schedule edit page JavaScript errors
Improves user experience with config title display
