F5 (dashboard): surface 'route unpublished' for unhealthy/restarting deployed apps

Traefik only publishes a route to a healthy container, so an unhealthy deployed app
returns 404 at its URL though the container runs — previously shown only as 'Nem
egészséges' with no hint the URL is dead. New routeUnpublished() funcmap helper +
a distinct indicator on the dashboard and stacks cards (gated on .Deployed). Tests:
routeUnpublished across all states, real templateFS parses with the funcmap, and the
card guard renders the indicator only for deployed+unhealthy.

controller/internal/web/templates/stacks.html

@@ -30,6 +30,9 @@
                     <a class="subdomain-link" href="https://{{$subdomain}}.{{$.Domain}}" target="_blank">
                         {{$subdomain}}.{{$.Domain}} ↗
                     </a>
+                    {{if and .Deployed (routeUnpublished .State)}}
+                    <span class="route-unpublished" title="A proxy (Traefik) csak egészséges konténerhez publikál nyilvános útvonalat. Amíg az alkalmazás nem egészséges, az URL nem érhető el (404), pedig a konténer fut.">⚠ URL nem elérhető – útvonal nincs publikálva</span>
+                    {{end}}
                     {{end}}
                 </div>
             </div>