refactor: remove unused imports in test files for improved code quality

src/tests/backend/callbacks/test_response_handlers.py

@@ -1,11 +1,8 @@
 """Unit tests for response_handlers module."""
 
-import asyncio
-import logging
 import os
 import sys
-import time
-from unittest.mock import AsyncMock, MagicMock, Mock, patch
+from unittest.mock import AsyncMock, Mock, patch
 
 import pytest
 

src/tests/backend/models/test_plan_models.py

@@ -4,8 +4,6 @@
 
 import uuid
 
-import pytest
-
 from backend.models.plan_models import (AgentDefinition, MPlan, MStep,
                                         PlannerResponsePlan,
                                         PlannerResponseStep, PlanStatus)

src/tests/backend/orchestration/helper/test_plan_to_mplan_converter.py

@@ -10,7 +10,6 @@
 """
 
 import os
-import re
 import sys
 import unittest
 

src/tests/backend/services/test_team_service.py

@@ -66,7 +66,7 @@ class MockDatabaseBase:
 
 # Mock common.models.messages with real dataclasses
 from dataclasses import dataclass, field
-from typing import Any, List, Optional
+from typing import Any, List
 
 
 @dataclass