fix: Caddy healthcheck use 127.0.0.1 (avoid IPv6 wget failure)

deploy/docker-compose.prod.yml

@@ -34,7 +34,7 @@ services:
       frontend:
         condition: service_healthy
     healthcheck:
-      test: ["CMD", "wget", "-qO-", "http://localhost:2019/metrics"]
+      test: ["CMD", "wget", "-qO-", "http://127.0.0.1:2019/metrics"]
       interval: 30s
       timeout: 10s
       retries: 3