Fix uvicorn startup: use python -m uvicorn to avoid venv shebang path issue

Author: python2121

Dockerfile

@@ -45,4 +45,4 @@ EXPOSE 8000
 HEALTHCHECK --interval=30s --timeout=5s --retries=3 \
   CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/')" || exit 1
 
-CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]
+CMD ["python", "-m", "uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]