Fixes:
- Fixed pinned tabs not persisting between app restarts – pin state is now saved to the session file and restored on launch
- Fixed local tabs being overwritten or deleted by stale CloudKit data during first sync after upgrade from 1.6.0 to 1.8.x – local state is now treated as authoritative until the first sync cycle completes
- Fixed tabs and clipboard history lost when upgrading from 1.6.x to 1.8.x – session data is now migrated from the non-sandboxed path to the sandboxed container on first launch