chore: polish code with little update (#182)

- Run Docker container as non-root user (appuser) to minimize security risks
- Add Docker HEALTHCHECK for better container orchestration
- Make CORS configurable via ALLOWED_ORIGINS env var with security warning
- Replace assertions with proper error handling (TypeError/ValueError)
- Add 30s timeout to HTTP requests to prevent hanging connections
- Disable auto-reload in production uvicorn settings

THIRD_PARTY

@@ -0,0 +1,8 @@
+certifi
+
+SPDX-License-Identifier: MPL-2.0
+This Source Code Form is subject to the terms of the Mozilla Public
+License, v. 2.0. If a copy of the MPL was not distributed with this
+file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+https://github.com/certifi/python-certifi