feat(trigger): enhance trigger management with new error handling and response structure

- Added `TriggerInvokeError` and `TriggerIgnoreEventError` for better error categorization during trigger invocation.
- Updated `TriggerInvokeResponse` to include a `cancelled` field, indicating if a trigger was ignored.
- Enhanced `TriggerManager` to handle specific errors and return appropriate responses.
- Refactored `dispatch_triggered_workflows` to improve workflow execution logic and error handling.

These changes improve the robustness and clarity of the trigger management system.

api/libs/schedule_utils.py

@@ -33,7 +33,7 @@ def calculate_next_run_at(
     parts = cron_expression.strip().split()
 
     # Support both 5-field format and predefined expressions (matching frontend)
-    if len(parts) != 5 and not cron_expression.startswith('@'):
+    if len(parts) != 5 and not cron_expression.startswith("@"):
         raise ValueError(
             f"Cron expression must have exactly 5 fields or be a predefined expression "
             f"(@daily, @weekly, etc.). Got {len(parts)} fields: '{cron_expression}'"