fix: change frontend healthcheck from wget to curl for Debian slim compatibility

- Switched from wget to curl for frontend healthcheck
- wget is not installed in node:20-slim (Debian-based)
- curl is pre-installed and compatible with Debian slim images
- Consistent with spawner API healthcheck (also uses curl)

docker-compose.yml

@@ -104,7 +104,7 @@ services:
 
     # Health-Check
     healthcheck:
-      test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://localhost:3000/"]
+      test: ["CMD", "curl", "-f", "http://localhost:3000/"]
       interval: 30s
       timeout: 10s
       retries: 3