Add registry to tailscale_serve configuration

Exposes zot registry (localhost:5000) as registry.tail8d86e.ts.net

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

ansible/roles/tailscale_serve/defaults/main.yml

@@ -35,3 +35,8 @@ tailscale_serve_services:
     https:
       port: 443
       upstream: http://localhost:8080
+
+  - name: svc:registry
+    https:
+      port: 443
+      upstream: http://localhost:5000