feat(trigger): implement debug session capabilities for trigger nodes

- Added `DraftWorkflowTriggerNodeApi` to handle debugging of trigger nodes, allowing for real-time event listening and session management.
- Introduced `TriggerDebugService` for managing debug sessions and event dispatching using Redis Pub/Sub.
- Updated `TriggerService` to support dispatching events to debug sessions and refactored related methods for improved clarity and functionality.
- Enhanced data structures in `request.py` and `entities.py` to accommodate new debug event data requirements.

These changes significantly improve the debugging capabilities for trigger nodes in draft workflows, facilitating better development and troubleshooting processes.

api/core/plugin/entities/request.py

@@ -1,3 +1,4 @@
+from collections.abc import Mapping
 from typing import Any, Literal, Optional
 
 from flask import Response
@@ -239,9 +240,11 @@ class RequestFetchAppInfo(BaseModel):
 
     app_id: str
 
+class Event(BaseModel):
+    variables: Mapping[str, Any]
 
 class TriggerInvokeResponse(BaseModel):
-    event: dict[str, Any]
+    event: Event
 
 
 class PluginTriggerDispatchResponse(BaseModel):