- Implemented ExportWindow class for exporting data and graphs in various formats (JSON, XML, PDF).
- Integrated ExportManager to handle export logic.
- Added export option in the main application menu.
- Enhanced user interface with data summary and export options.
- Included error handling and success messages for export operations.
- Updated dependencies in the lock file to include reportlab and lxml for PDF generation.
- Deleted `TESTING_SETUP.md` and `TEST_UPDATES_SUMMARY.md` as they were outdated.
- Introduced `CHANGELOG.md` to document notable changes and version history.
- Added `DEVELOPMENT.md` for detailed development setup, testing framework, and debugging guidance.
- Created `FEATURES.md` to outline core features and functionalities of TheChart.
- Established `README.md` as a centralized documentation index for users and developers.
