fix(ui): listen on 8080 to match the UI image's own port

docker-compose.yml

@@ -141,7 +141,7 @@ services:
     image: quay.io/duplocloud/duplo-ai-helpdesk-ui:${UI_TAG}
     restart: unless-stopped
     ports:
-      - "${UI_PORT:-4200}:80"
+      - "${UI_PORT:-4200}:8080"
     volumes:
       # Published image serves the SPA only; this conf proxies API prefixes to the studio (same-origin, no CORS).
       - ./nginx/default.conf:/etc/nginx/conf.d/default.conf:ro

nginx/default.conf

@@ -1,9 +1,11 @@
 # Dev-kit nginx config for the UI image. The published image serves the SPA only (no API proxy),
 # and the app calls the API same-origin (apiUrl "/"). Here we proxy the API path prefixes to the
 # studio container so the browser stays same-origin — no CORS needed. Mounted over
-# /etc/nginx/conf.d/default.conf by docker-compose.
+# /etc/nginx/conf.d/default.conf by docker-compose. Listen on 8080, the port the image itself serves on:
+# its baked-in healthcheck probes 127.0.0.1:8080, so a conf that listens elsewhere serves fine but reports
+# the container permanently (unhealthy).
 server {
-    listen 80;
+    listen 8080;
     server_name _;
     root /usr/share/nginx/html;
     index index.html;