chore(docker): update healthcheck to use /api/health endpoint

Use the dedicated health API endpoint instead of the root dashboard
route for more accurate container health monitoring.

docker-compose.yml

@@ -36,7 +36,7 @@ services:
     ports:
       - "5000:5000"
     healthcheck:
-      test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://localhost:5000/')"]
+      test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://localhost:5000/api/health')"]
       interval: 30s
       timeout: 10s
       retries: 3