feat: comprehensive test infrastructure improvements

- Fix unit test imports: add env setup in conftest.py before module imports
- Add 24 new auth router tests (RBAC, preferences, password validation)
- Add 16 new tests for litellm and chat_summary routers
- Apply black formatting and ruff linting across codebase
- Add pre-commit hooks configuration (black, ruff, file checks)
- Increase CI coverage threshold from 40% to 50%

Test Results:
- 206 tests passing (91 unit + 115 integration)
- Coverage: 58.79% on core modules
- auth.py: 57% → 85%, litellm.py: 23% → 87%, chat_summary.py: 41% → 100%
- auth_service: 96.51%, config: 100%, rbac: 93.48%

dashboard/backend/routers/opc_ws.py

@@ -1,20 +1,19 @@
 """
 OPC WebSocket Router - Real-time updates for tasks and agent executions
 """
-from fastapi import APIRouter, WebSocket, WebSocketDisconnect, Depends
-from typing import Set, Any, Dict
-from datetime import datetime
-import json
-import asyncio
+
 import logging
-from auth_service import get_current_user_ws
+from datetime import datetime
+from typing import Any
+
+from fastapi import APIRouter, WebSocket, WebSocketDisconnect
 
 logger = logging.getLogger(__name__)
 
 router = APIRouter()
 
 # Active WebSocket connections
-active_connections: Set[WebSocket] = set()
+active_connections: set[WebSocket] = set()
 
 
 def serialize_datetime(obj: Any) -> Any:
@@ -33,7 +32,7 @@ class ConnectionManager:
     """Manages WebSocket connections"""
 
     def __init__(self):
-        self.active_connections: Set[WebSocket] = set()
+        self.active_connections: set[WebSocket] = set()
 
     async def connect(self, websocket: WebSocket):
         """Accept and register a new connection"""
@@ -95,7 +94,7 @@ async def broadcast_task_update(task_id: int, action: str, task_data: dict):
         "task_id": task_id,
         "action": action,  # created, updated, moved, deleted
         "data": serialized_data,
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": datetime.utcnow().isoformat(),
     }
     await manager.broadcast(message)
 
@@ -110,7 +109,7 @@ async def broadcast_agent_execution(execution_id: int, status: str, execution_da
         "execution_id": execution_id,
         "status": status,  # pending, running, completed, failed, pending_approval
         "data": serialized_data,
-        "timestamp": datetime.utcnow().isoformat()
+        "timestamp": datetime.utcnow().isoformat(),
     }
     await manager.broadcast(message)
 
@@ -121,6 +120,6 @@ async def broadcast_agent_status(agent_id: str, status: str, message_text: str =
         "type": "agent_status",
         "agent_id": agent_id,
         "status": status,  # idle, working, error
-        "message": message_text
+        "message": message_text,
     }
     await manager.broadcast(message)