fix(dashboard): add explicit tailscale.com/ports: "http:3000" annotation

Matches the exact annotation pattern used for other tailnet services (Grafana, trade-dashboard, hermes-webui, etc.).

This ensures the Tailscale operator correctly maps the exposed port after the 3000 change.

apps/base/customer1/trading-platform/dashboard/service.yaml

@@ -7,12 +7,12 @@ metadata:
     tailscale.com/expose: "true"
     tailscale.com/hostname: "trading-dashboard"
     tailscale.com/tags: "tag:k8s-operator"
-    tailscale.com/ports: "http:80"
+    tailscale.com/ports: "http:3000"
 spec:
   selector:
     app: trading-dashboard
   ports:
-    - port: 80
+    - port: 3000
       targetPort: 3000
       name: http
   type: ClusterIP