F5 (dashboard): surface 'route unpublished' for unhealthy/restarting deployed apps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

@@ -149,6 +149,7 @@
         <div class="stack-actions">
             <span class="stack-state-label">{{stateLabel .State}}</span>
             {{if .Orphaned}}<span class="badge badge-orphaned">Elavult</span>{{end}}
+            {{if and .Deployed (routeUnpublished .State)}}<span class="badge badge-route-unpublished" title="A proxy (Traefik) csak egészséges konténerhez publikál nyilvános útvonalat. Amíg az alkalmazás nem egészséges, az URL 404-et ad, pedig a konténer fut.">⚠ URL nem elérhető</span>{{end}}
 
             {{if .Protected}}
                 <span class="badge badge-protected">Védett</span>