Feature: Centralized Configuration Management with Pydantic and python-dotenv

[lanceherman]

This PR sets up a centralized configuration system for the FastAPI app, making it easier to manage environment variables.

Changes

• Introduced app/core/config.py to define app settings using pydantic.BaseSettings.
• Configured core settings like APP_NAME, DEBUG, API_V1_PREFIX, and DATABASE_URL to load from environment variables.
• Added a .env file at the project root for local development.
• Integrated python-dotenv to ensure environment variables are loaded correctly.
• Updated main.py to import and use the new configuration module for consistent settings across the application.

[felixjordandev]

Nice, the introduction of pydantic for settings will streamline our config management.