Save freeze fix:
- Added record_symlinks_batch() that inserts all symlinks in a single
DB transaction instead of opening a new connection per file
- _save_session and _auto_save_session now use batch inserts
- With 1700 files this goes from 1700 connection cycles to 1
Removed files fix:
- _restore_files_from_session now filters by _removed_files so
individually deleted files stay removed even when restoring from
session data that pre-dates the removal
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>