Fix zerotier UI port and traefik basicAuth mount

- zerotier: Change exposed port from 3180 to 3000 (actual UI port)
- zerotier: Add loadbalancer.server.port label for traefik
- traefik: Add basicAuth volume mount for dashboard-auth middleware
- test-services.sh: Fix registry URL to use /v2/ endpoint

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

scripts/test-services.sh

@@ -26,7 +26,7 @@ URLS=(
     "https://inv.$DOMAIN"
     "https://memento.$DOMAIN"
     "https://radicale.$DOMAIN"
-    "https://registry.$DOMAIN"
+    "https://registry.$DOMAIN/v2/"
     "https://smoke.$DOMAIN"
     "https://syncthing.$DOMAIN"
     "https://wallabag.$DOMAIN"