Track legacy deletions.jsonl entries converted to tombstones during import: - Add Result.ConvertedToTombstone counter - Add Result.ConvertedTombstoneIDs for the converted IDs - Update test to verify the new counter 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>