chore: fix all ruff lint errors + format — 0 errors, 306 tests pass

app/core/event_bus.py

@@ -4,7 +4,8 @@ from __future__ import annotations
 
 import asyncio
 from collections import defaultdict
-from typing import Any, Callable, Coroutine
+from collections.abc import Callable, Coroutine
+from typing import Any
 
 EventHandler = Callable[[dict[str, Any]], Coroutine[Any, Any, None]]
 
@@ -48,4 +49,5 @@ def register_workflow_event_handlers() -> None:
     Should be called during application startup.
     """
     from app.workflows.engine import register_workflow_event_handlers as _register
+
     _register()