feat: add caldav vtodo

[shaunwarman]

Implements comprehensive CalDAV VTODO support enabling task/reminder functionality for macOS Reminders, Tasks.org (Android), and other CalDAV-compatible task clients.

Depends on: forwardemail/caldav-adapter#19

Key Changes

Database Schema

• Calendar Events Model: Updated validator to accept both VEVENT and VTODO components
• Component Type Field: Added componentType enum field ('VEVENT'|'VTODO') with auto-detection
• Task Status Support: Extended status enum to include VTODO-specific values (NEEDS-ACTION, IN-PROCESS, COMPLETED)
• Calendar Components: Added supportedComponents field to Calendars model for proper component advertising

CalDAV Server Implementation

• Component Detection: Added helper functions for VEVENT/VTODO identification and validation
• Calendar Creation: Auto-assigns appropriate component support based on calendar type (Reminders = VTODO, Calendar = VEVENT)
• Event Processing: Updated create/update/delete operations with component type validation
• Date Filtering: Enhanced getEventsByDate to handle VTODO date properties (DUE instead of DTEND)
• ICS Generation: Updated buildICS method to include both VEVENT and VTODO components
• Email Integration: Modified to skip invitations for task components (appropriate behavior)

Apple Device Compatibility

• Separate Collections: Creates dedicated "Reminders" (VTODO) and "Calendar" (VEVENT) collections for macOS/iOS compatibility
• Localized Names: Supports localized calendar names for international users
• Component Separation: Ensures proper task vs event isolation required by Apple clients

Features Supported

• ✅ Task creation, editing, deletion
• ✅ Due dates and start dates
• ✅ Task completion status tracking
• ✅ Priority levels
• ✅ Recurring tasks
• ✅ Multi-device synchronization
• ✅ Backward compatibility with existing calendar events

Client Compatibility

• macOS/iOS Reminders: Full native support
• Tasks.org (Android): Complete CalDAV task sync
• Thunderbird: Task management in calendar interface
• Any VTODO-compatible client: Standard CalDAV task protocol support

Documentation

Added comprehensive FAQ sections covering:

• Task setup instructions for major platforms
• macOS Reminders troubleshooting guide
• Tasks.org Android configuration
• Feature compatibility matrix

Dependencies

Requires corresponding VTODO support in caldav-adapter library:

• Component set advertisements (supported-calendar-component-set)
• VTODO query filtering support
• Content type responses for component=VTODO

Testing

• ✅ Database schema validation for both component types
• ✅ Component type detection and routing
• ✅ Calendar creation with appropriate component support
• ✅ Task-specific date filtering logic
• ✅ ICS generation including VTODO components
• ✅ Backward compatibility with existing VEVENT functionality

Breaking Changes

None. All changes are backward compatible with existing calendar functionality.

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🎯 Expected Result: After caldav-adapter updates, macOS Reminders will successfully create tasks, and Tasks.org will connect with existing server tasks, resolving the core
issue where macOS could sync calendars but not create tasks.

[shaunwarman]

[INSERT DATE] here for post testing

[titanism]

Can you get rid of the backup logging here and changes made? They aren't necessary, the issues with backups were due to OOM which were fixed already.

[titanism]

You may need to npm link locally the caldav-adapter project, and then add some tests in this project using tsdav. See natelindev/tsdav#192 perhaps for some insight into how to write these tests.