Commit each schema migration separately on PostgreSQL.

Co-authored-by: Cursor <cursoragent@cursor.com>

app.py

@@ -373,11 +373,11 @@ def init_db():
     for sql in migrations:
         try:
             c.execute(sql)
+            conn.commit()
         except Exception as exc:
             if not is_schema_migration_error(exc):
                 raise
             rollback_if_postgres(conn)
-    conn.commit()
     c.execute('''CREATE TABLE IF NOT EXISTS review_records
                  (id INTEGER PRIMARY KEY AUTOINCREMENT,
                   open_time TEXT, close_time TEXT,
@@ -430,6 +430,7 @@ def init_db():
     ):
         try:
             c.execute(sql)
+            conn.commit()
         except Exception as exc:
             if not is_schema_migration_error(exc):
                 raise