Phase 3 Step 6: Complete Scheduler Integration with Bug Fixes

Implemented complete scheduler integration with automatic schedule loading,
orphaned scan cleanup, and conversion to local timezone for better UX.

Backend Changes:
- Added load_schedules_on_startup() to load enabled schedules on app start
- Implemented cleanup_orphaned_scans() to handle crashed/interrupted scans
- Converted scheduler from UTC to local system timezone throughout
- Enhanced scheduler service with robust error handling and logging

Frontend Changes:
- Updated all schedule UI templates to display local time instead of UTC
- Improved timezone indicators and user messaging
- Removed confusing timezone converter (no longer needed)
- Updated quick templates and help text for local time

Bug Fixes:
- Fixed critical timezone bug causing cron expressions to run at wrong times
- Fixed orphaned scans stuck in 'running' status after system crashes
- Improved time display clarity across all schedule pages

All schedules now use local system time for intuitive scheduling.

web/app.py

@@ -294,11 +294,23 @@ def init_scheduler(app: Flask) -> None:
         app: Flask application instance
     """
     from web.services.scheduler_service import SchedulerService
+    from web.services.scan_service import ScanService
 
     # Create and initialize scheduler
     scheduler = SchedulerService()
     scheduler.init_scheduler(app)
 
+    # Perform startup tasks with app context for database access
+    with app.app_context():
+        # Clean up any orphaned scans from previous crashes/restarts
+        scan_service = ScanService(app.db_session)
+        orphaned_count = scan_service.cleanup_orphaned_scans()
+        if orphaned_count > 0:
+            app.logger.warning(f"Cleaned up {orphaned_count} orphaned scan(s) on startup")
+
+        # Load all enabled schedules from database
+        scheduler.load_schedules_on_startup()
+
     # Store in app context for access from routes
     app.scheduler = scheduler