feat: Add CardDAV/VTODO integration tests and fix Nextcloud addressbo…

[PhilflowIO]

…ok bugs

Implements comprehensive test coverage for issue #27 (CardDAV and VTODO migration) and fixes critical bugs preventing Nextcloud addressbook operations.

Production validation: Successfully migrated 131 contacts from Radicale to Nextcloud.

Bug Fixes (AddressBookCollectionMigrator):

• Fix addressbook home URL construction for Nextcloud provider

  • Now correctly uses /remote.php/dav/addressbooks/users/{username}/
  • Added provider-specific URL logic (Nextcloud, generic CardDAV)
  • Fallback handling with warnings for unknown providers

• Add required resourcetype property to addressbook creation

  • Includes both d:collection and carddav:addressbook types
  • Complies with RFC 5689 (Extended MKCOL for WebDAV)

• Implement homeUrl override for fetchAddressBooks

  • Ensures addressbooks are discovered at correct CardDAV endpoints
  • Properly restores original homeUrl after operations
  • Works for both source and target servers

New Test Files:

• tests/integration/contacts.integration.test.ts (5 tests)

  • Full migration (15 contacts)
  • Multi-addressbook (3 addressbooks, 18 contacts)
  • DSGVO compliance verification
  • State persistence
  • Empty addressbook handling

• tests/integration/vtodo.integration.test.ts (6 tests)

  • Task-only calendar (10 tasks)
  • Mixed calendar (5 events + 3 tasks)
  • Multiple calendars (events/tasks/mixed)
  • Object type detection (VEVENT vs VTODO)
  • Empty calendar handling
  • Large task collection (50 tasks)

Code Coverage:

• CalendarCollectionMigrator: 86.45% (exceeds 80% target)
• AddressBookCollectionMigrator: 74.6% (core logic fully covered)

Dependencies:

• Added cross-fetch for fetch polyfill
• Updated tsdav to ^2.1.6 for makeAddressBook support

Test Results:

• 11 new integration tests (all passing)
• DSGVO compliance verified (zero contact data in state files)
• Production validated (131 contacts successfully migrated)

Closes #27