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>

stacks/traefik/docker-compose.yml

@@ -18,6 +18,7 @@ services:
       - ./traefik.yml:/traefik.yml:ro
       - ./acme.json:/acme.json
       - ./conf.d/:/conf.d/
+      - ./basicAuth:/basicAuth:ro
       - /var/log:/var/log
 
 networks: