Update backend configuration and documentation

- Modified main.py with backend updates
- Updated Tasks.md documentation

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/app/main.py

@@ -12,6 +12,7 @@ on ``app.state`` throughout the request lifecycle.
 from __future__ import annotations
 
 import logging
+import re
 import sys
 from contextlib import asynccontextmanager
 from typing import TYPE_CHECKING
@@ -196,7 +197,6 @@ def _get_error_code(exc: Exception) -> str:
         return exc.error_code
 
     exc_name = exc.__class__.__name__
-    import re
     snake_case = re.sub(r"(?<!^)(?=[A-Z])", "_", exc_name).lower()
     return snake_case