Add end-to-end tests for parent item management

- Implement tests for creating, editing, and deleting chores, kindness acts, and penalties.
- Add tests to verify conversion of default items to user items and restoration of system defaults upon deletion.
- Ensure proper cancellation of creation and editing actions.
- Create a comprehensive plan document outlining the test scenarios and expected behaviors.

backend/config/paths.py

@@ -26,6 +26,12 @@ def get_database_dir(db_env: str | None = None) -> str:
     env = (db_env or os.environ.get('DB_ENV', 'prod')).lower()
     return os.path.join(PROJECT_ROOT, get_base_data_dir(env), 'db')
 
+def get_images_dir() -> str:
+    """
+    Return the absolute directory path for storing images.
+    """
+    return os.path.join(PROJECT_ROOT, get_base_data_dir(), 'images')
+
 def get_user_image_dir(username: str | None) -> str:
     """
     Return the absolute directory path for storing images for a specific user.