Refresh and modernize the codebase

[CodeHalwell]

Goal:

• Modernize the codebase for CodeHalwell/code_chat_bot to improve maintainability, reliability, and developer experience.

Tasks:

1. Update All Libraries:
   • Audit and upgrade all dependencies to their latest stable versions.
   • Ensure compatibility and resolve any breaking changes during the update process.
2. Switch to uv Package Manager:
   • Replace the current package management workflow (pip/Poetry/Pipenv/etc.) with uv.
   • Update documentation to reflect new installation and development commands.
3. Refactor to Modular Format:
   • Break down monolithic scripts or classes into clear, modular components.
   • Organize code for readability, reusability, and testability.
   • Apply standard project structures (e.g., src/ directory, init.py, etc.).
4. Introduce Pydantic:
   • Use Pydantic for data validation and parsing, especially for API inputs/outputs and configuration.
   • Refactor existing dataclasses or manual validation logic to use Pydantic models where appropriate.

Acceptance Criteria:

• All dependencies are up to date and installed via uv.
• The project structure is modular and clean.
• Pydantic is used for all data modeling and validation needs.
• CI passes and documentation is updated accordingly.