feat: add vtodo support

[shaunwarman]

Added comprehensive VTODO (task/todo) support to the CalDAV adapter, enabling clients like macOS Reminders and task management apps to create, query, and manage todo items
alongside existing calendar events.

Changes

• Component Discovery: Updated supported-calendar-component-set to advertise VTODO support
• Content Types: Enhanced content type responses to handle both VEVENT and VTODO components dynamically
• Query Support: Extended calendar-query filtering to support VTODO time-range queries
• Data Integration: Updated data layer calls to pass component type for proper filtering
• Standards Compliance: Maintains backward compatibility while following RFC 4791 CalDAV specification

Test Plan

• Verify existing VEVENT functionality remains unchanged
• Test VTODO component discovery through supported-calendar-component-set
• Validate calendar-query with VTODO filters
• Confirm content type responses for VTODO resources
• Test with CalDAV clients (macOS Reminders, Tasks.org, etc.)