fix(migrations): add schema_version inserts to migrations 022-027

Defense-in-depth: The migration framework already handles missing
inserts via INSERT OR REPLACE (db.rs:174), but adding explicit
inserts to .sql files ensures consistency and makes migrations
self-documenting.

Migrations affected:
- 022_notes_query_index
- 024_note_documents  
- 025_note_dirty_backfill
- 026_scoring_indexes
- 027_surgical_sync_runs

migrations/025_note_dirty_backfill.sql

@@ -6,3 +6,6 @@ FROM notes n
 LEFT JOIN documents d ON d.source_type = 'note' AND d.source_id = n.id
 WHERE n.is_system = 0 AND d.id IS NULL
 ON CONFLICT(source_type, source_id) DO NOTHING;
+
+INSERT INTO schema_version (version, applied_at, description)
+VALUES (25, strftime('%s', 'now') * 1000, '025_note_dirty_backfill');