- Created a new `CHANGELOG.md` file to document all notable changes to the project, adhering to the Keep a Changelog format.
- Updated `CONTRIBUTING.md` to include instructions for building and previewing documentation using MkDocs.
- Added `mkdocs.yml` configuration for documentation generation, including navigation structure and theme settings.
- Enhanced various documentation files, including API reference, architecture overview, configuration reference, and runbook, to provide comprehensive guidance for users and developers.
- Included new sections in the README for changelog and documentation links, improving accessibility to project information.
- Introduced a new database model for calendar subscription tokens, allowing users to generate unique tokens for accessing their personal calendar.
- Implemented API endpoint to return ICS files containing only the subscribing user's duties, enhancing user experience with personalized calendar access.
- Added utility functions for generating ICS files from user duties, ensuring proper formatting and timezone handling.
- Updated command handlers to support the new calendar link feature, providing users with easy access to their personal calendar subscriptions.
- Included unit tests for the new functionality, ensuring reliability and correctness of token generation and ICS file creation.
