test(electric-db-collection): add move-in and DNF coverage tests

Add tests ported from the Elixir client's tag_tracker_test.exs:
- Move-in activates correct positions
- Move-out → move-in → move-out full lifecycle cycle
- Deleted rows not resurrected by move-in (tag index cleaned up)
- Orphaned tag index entries don't cause phantom deletes
- Deleted row cleans up ALL tag index entries
- Multiple patterns deactivating same row in one call
- Unit tests for parseTag, rowVisible, and deriveDisjunctPositions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: kevin-dp