feat: Remove unused imports from test files for cleaner code

tests/test_ui_manager.py

@@ -5,8 +5,7 @@ import os
 import pytest
 import tkinter as tk
 from tkinter import ttk
-from unittest.mock import Mock, patch, MagicMock
-from datetime import datetime
+from unittest.mock import Mock, patch
 
 import sys
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))