Add healthz endpoint and increase Gunicorn timeout

Dockerfile

@@ -95,4 +95,4 @@ ENTRYPOINT []
 # Use the port defined by FLASK_RUN_PORT
 # The number of workers (e.g., --workers 3) can be adjusted based on server resources
 # Use JSON form with the absolute path to gunicorn in the venv to avoid PATH issues
-CMD ["/app/venv/bin/gunicorn", "--workers", "3", "--bind", "0.0.0.0:5001", "app:app"]
+CMD ["/app/venv/bin/gunicorn", "--workers", "3", "--bind", "0.0.0.0:5001", "--timeout", "60", "app:app"]

app.py

@@ -175,6 +175,9 @@ def preview_mermaid():
              except OSError as e:
                  logging.error(f"Error deleting temporary input file {input_path} after download: {e}")
 
+@app.route('/healthz')
+def healthz():
+    return "OK", 200
 
 if __name__ == '__main__':
     # For local development only (use Gunicorn/Waitress in production)