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/services/scan_service.py

@@ -268,6 +268,53 @@ class ScanService:
 
         return status_info
 
+    def cleanup_orphaned_scans(self) -> int:
+        """
+        Clean up orphaned scans that are stuck in 'running' status.
+
+        This should be called on application startup to handle scans that
+        were running when the system crashed or was restarted.
+
+        Scans in 'running' status are marked as 'failed' with an appropriate
+        error message indicating they were orphaned.
+
+        Returns:
+            Number of orphaned scans cleaned up
+        """
+        # Find all scans with status='running'
+        orphaned_scans = self.db.query(Scan).filter(Scan.status == 'running').all()
+
+        if not orphaned_scans:
+            logger.info("No orphaned scans found")
+            return 0
+
+        count = len(orphaned_scans)
+        logger.warning(f"Found {count} orphaned scan(s) in 'running' status, marking as failed")
+
+        # Mark each orphaned scan as failed
+        for scan in orphaned_scans:
+            scan.status = 'failed'
+            scan.completed_at = datetime.utcnow()
+            scan.error_message = (
+                "Scan was interrupted by system shutdown or crash. "
+                "The scan was running but did not complete normally."
+            )
+
+            # Calculate duration if we have a started_at time
+            if scan.started_at:
+                duration = (datetime.utcnow() - scan.started_at).total_seconds()
+                scan.duration = duration
+
+            logger.info(
+                f"Marked orphaned scan {scan.id} as failed "
+                f"(started: {scan.started_at.isoformat() if scan.started_at else 'unknown'})"
+            )
+
+        self.db.commit()
+        logger.info(f"Cleaned up {count} orphaned scan(s)")
+
+        return count
+
     def _save_scan_to_db(self, report: Dict[str, Any], scan_id: int,
                         status: str = 'completed') -> None:
         """