feat: Enhance CSV export process with configurable note limits and README generation

- Added support for a maximum notes per country limit in the export process, defaulting to 400,000 to comply with GitHub's file size restrictions.
- Updated SQL queries to incorporate the new limit, ensuring only the most recent notes are exported for AI context.
- Implemented a function to generate a README.md file that documents available countries and their corresponding CSV files, improving usability and clarity.
- Enhanced the commit and push logic to handle merge conflicts more effectively, ensuring smoother updates to the GitHub repository.

Author: angoca