fix: Correct alembic upgrade command from head to heads.

docker-entrypoint.sh

@@ -5,7 +5,7 @@ echo "Setting up screenshots directory..."
 mkdir -p screenshots
 
 echo "Running database migrations..."
-alembic upgrade head
+alembic upgrade heads
 
 echo "Starting application..."
 exec uvicorn app.main:app --host 0.0.0.0 --port 8555