- Updated import statements to remove invisible characters.
- Standardized comments to use a consistent hyphen format.
- Adjusted username validation error messages for consistency.
- Enhanced email sending functions to include language support.
- Added email internationalization configuration for dynamic translations.
- Updated calendar and federation routes to include language in user queries.
- Improved user feedback messages in German and English for clarity.
- Added functionality to create, accept, decline, and delete local calendar invitations.
- Integrated email notifications for calendar event invitations and deletions.
- Updated database schema to support local invitations and outbound event tracking.
- Enhanced the calendar UI to display pending invitations and allow users to manage them.
- Localized new strings for invitations in English and German.
