fix: Ensure migration_state updates are committed to database

The _update_migration_state() method was using pg_conn.execute() which has
its own connection management. This could cause issues with transaction
handling when called at end of migration.

Changed to use explicit cursor with guaranteed commit:
- Use pg_conn.connection.cursor() to get a direct cursor
- Execute the INSERT ... ON CONFLICT query
- Explicitly call pg_conn.connection.commit()
- This matches the pattern used in other parts of the code

This ensures that final migration state (completed status, final counts)
are properly persisted to the database.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/migrator/full_migration.py

@@ -255,30 +255,30 @@ class FullMigrator:
 
         # Update PostgreSQL migration_state table
         try:
-            # Use COALESCE to handle both insert (first time) and update (resume)
+            with pg_conn.connection.cursor() as cursor:
-            # For resume: total_rows_migrated will be the full accumulated count
+                query = f"""
-            query = f"""
+                    INSERT INTO migration_state
-                INSERT INTO migration_state
+                    (table_name, last_migrated_timestamp, last_migrated_id, total_rows_migrated, migration_completed_at, status)
-                (table_name, last_migrated_timestamp, last_migrated_id, total_rows_migrated, migration_completed_at, status)
+                    VALUES (%s, %s, %s, %s, %s, %s)
-                VALUES (%s, %s, %s, %s, %s, %s)
+                    ON CONFLICT (table_name) DO UPDATE SET
-                ON CONFLICT (table_name) DO UPDATE SET
+                        last_migrated_timestamp = EXCLUDED.last_migrated_timestamp,
-                    last_migrated_timestamp = EXCLUDED.last_migrated_timestamp,
+                        last_migrated_id = EXCLUDED.last_migrated_id,
-                    last_migrated_id = EXCLUDED.last_migrated_id,
+                        total_rows_migrated = EXCLUDED.total_rows_migrated,
-                    total_rows_migrated = EXCLUDED.total_rows_migrated,
+                        migration_completed_at = EXCLUDED.migration_completed_at,
-                    migration_completed_at = EXCLUDED.migration_completed_at,
+                        status = EXCLUDED.status
-                    status = EXCLUDED.status
+                """
-            """
+                cursor.execute(
-            pg_conn.execute(
+                    query,
-                query,
+                    (
-                (
+                        pg_table,
-                    pg_table,
+                        migration_start_time or now.isoformat(),
-                    migration_start_time or now.isoformat(),
+                        last_id,
-                    last_id,
+                        rows_migrated,
-                    rows_migrated,
+                        now if status == "completed" else None,
-                    now if status == "completed" else None,
+                        status
-                    status
+                    )
                 )
-            )
+                pg_conn.connection.commit()
             logger.debug(f"Migration state updated: {rows_migrated} rows total, last_id={last_id}, status={status}")
         except Exception as e:
             logger.warning(f"Failed to update migration state in PostgreSQL: {e}")