Fix health check to use IPv4

Health check was using localhost which resolved to IPv6 [::1],
but the server binds to 0.0.0.0. Changed to 127.0.0.1.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.yml

@@ -29,7 +29,7 @@ services:
     networks:
       - traefik-public
     healthcheck:
-      test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://localhost:3000/health"]
+      test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://127.0.0.1:3000/health"]
       interval: 30s
       timeout: 3s
       retries: 3