fix: use server.localhost subdomain for server-ui (same /assets conflict)

Server UI assets also use absolute /assets/* paths that conflict with
the SPA catch-all. Same fix as Logto: Host-based routing at
server.localhost gives it its own namespace.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -170,10 +170,8 @@ services:
       CAMELEER_API_URL: http://cameleer3-server:8081
     labels:
       - traefik.enable=true
-      - traefik.http.routers.server-ui.rule=PathPrefix(`/server`)
+      - traefik.http.routers.server-ui.rule=Host(`server.${PUBLIC_HOST:-localhost}`)
       - traefik.http.routers.server-ui.service=server-ui
-      - traefik.http.routers.server-ui.middlewares=server-ui-strip
-      - traefik.http.middlewares.server-ui-strip.stripprefix.prefixes=/server
       - traefik.http.services.server-ui.loadbalancer.server.port=80
     networks:
       - cameleer