feat: Refactor template handling, improve scheduler functions, and add timezone utilities

- Moved Jinja2 template setup to a shared configuration file (templates_config.py) for consistent usage across routers.
- Introduced timezone utilities in a new module (timezone.py) to handle UTC to local time conversions and formatting.
- Updated all relevant routers to use the new shared template configuration and timezone filters.
- Enhanced templates to utilize local time formatting for various datetime fields, improving user experience with timezone awareness.

backend/services/recurring_schedule_service.py

@@ -146,13 +146,22 @@ class RecurringScheduleService:
             return False
 
         # Delete pending generated actions for this schedule
-        # Note: We don't have recurring_schedule_id field yet, so we can't clean up
-        # generated actions. This is fine for now.
+        # The schedule_id is stored in the notes field as JSON
+        pending_actions = self.db.query(ScheduledAction).filter(
+            and_(
+                ScheduledAction.execution_status == "pending",
+                ScheduledAction.notes.like(f'%"schedule_id": "{schedule_id}"%'),
+            )
+        ).all()
+
+        deleted_count = len(pending_actions)
+        for action in pending_actions:
+            self.db.delete(action)
 
         self.db.delete(schedule)
         self.db.commit()
 
-        logger.info(f"Deleted recurring schedule: {schedule.name}")
+        logger.info(f"Deleted recurring schedule: {schedule.name} (and {deleted_count} pending actions)")
         return True
 
     def enable_schedule(self, schedule_id: str) -> Optional[RecurringSchedule]: