fix(router): Replace requests with urllib in healthcheck

- Use stdlib urllib.request instead of requests library
- requests was not installed in the router image, causing healthcheck
  to always fail with "ModuleNotFoundError: No module named 'requests'"
- Increase start_period to 30s and retries to 5 for stability

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

services/router/Dockerfile

@@ -12,9 +12,9 @@ COPY . .
 # Expose port
 EXPOSE 8000
 
-# Health check
-HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
-  CMD python -c "import requests; requests.get('http://localhost:8000/health')"
+# Health check (using urllib - no external deps)
+HEALTHCHECK --interval=30s --timeout=10s --start-period=30s --retries=5 \
+  CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/health')"
 
 # Run application
 CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]