ImportError: ImportError: cannot import name 'BaseSettings' from 'pydantic'

Root cause

The project is running with Pydantic v2, where BaseSettings was removed from pydantic and moved into the separate pydantic-settings package. app/config.py still uses the Pydantic v1 import path: `from pydantic import BaseSettings, Field`.

Minimal fix

Add `pydantic-settings` to the project dependencies, then update the settings module to import `BaseSettings` from `pydantic_settings` while keeping `Field` imported from `pydantic`, e.g. `from pydantic import Field` and `from pydantic_settings import BaseSettings`.