feat: catch-all page for stopped apps, deploy controls, dashboard open button

Stopped/undeployed app subdomains now show a branded page instead of
Traefik 404. Deploy settings page gains start/stop/restart controls.
Dashboard shows "Megnyitás" button for running apps.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/web/server.go

@@ -285,6 +285,88 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+// CatchAllMiddleware intercepts requests to non-controller hosts and serves
+// a branded error page (for stopped/undeployed app subdomains). Requests to
+// the controller host (felhom.DOMAIN) pass through normally.
+func (s *Server) CatchAllMiddleware(next http.Handler) http.Handler {
+	controllerHost := "felhom." + s.cfg.Customer.Domain
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		host := r.Host
+		if idx := strings.LastIndex(host, ":"); idx != -1 {
+			host = host[:idx]
+		}
+		if strings.EqualFold(host, controllerHost) || host == "" {
+			next.ServeHTTP(w, r)
+			return
+		}
+		s.serveCatchAll(w, r, host)
+	})
+}
+
+// serveCatchAll renders a branded page for requests reaching a stopped/undeployed
+// app subdomain. Served without auth since the user has no session on this host.
+func (s *Server) serveCatchAll(w http.ResponseWriter, r *http.Request, host string) {
+	domain := s.cfg.Customer.Domain
+	subdomain := ""
+	suffix := "." + domain
+	if strings.HasSuffix(host, suffix) {
+		subdomain = strings.TrimSuffix(host, suffix)
+	}
+
+	data := map[string]interface{}{
+		"Domain":        domain,
+		"ControllerURL": "https://felhom." + domain,
+		"Host":          host,
+	}
+
+	if subdomain != "" {
+		if stack, ok := s.findStackBySubdomain(subdomain); ok {
+			data["AppName"] = stack.Meta.DisplayName
+			data["AppSlug"] = stack.Meta.Slug
+			data["AppLogoURL"] = s.cfg.AppLogoURL(stack.Meta.Slug)
+			if stack.Deployed {
+				data["Status"] = "stopped"
+				data["StatusText"] = "Az alkalmazás jelenleg le van állítva"
+			} else {
+				data["Status"] = "not_deployed"
+				data["StatusText"] = "Az alkalmazás nincs telepítve"
+			}
+		} else {
+			data["Status"] = "unknown"
+			data["StatusText"] = "Ez az oldal nem található"
+		}
+	} else {
+		data["Status"] = "unknown"
+		data["StatusText"] = "Ez az oldal nem található"
+	}
+
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.WriteHeader(http.StatusNotFound)
+	if err := s.tmpl.ExecuteTemplate(w, "catchall", data); err != nil {
+		s.logger.Printf("[ERROR] Catch-all template error: %v", err)
+		http.Error(w, "Internal error", http.StatusInternalServerError)
+	}
+}
+
+// findStackBySubdomain looks up the stack that owns the given subdomain.
+func (s *Server) findStackBySubdomain(subdomain string) (*stacks.Stack, bool) {
+	for _, stack := range s.stackMgr.GetStacks() {
+		// Check deployed app.yaml SUBDOMAIN env first
+		if stack.Deployed {
+			if appCfg := s.stackMgr.LoadAppConfigByName(stack.Name); appCfg != nil {
+				if sd, ok := appCfg.Env["SUBDOMAIN"]; ok && sd == subdomain {
+					return &stack, true
+				}
+			}
+		}
+		// Fallback to metadata subdomain
+		if stack.Meta.Subdomain == subdomain {
+			return &stack, true
+		}
+	}
+	return nil, false
+}
+
 // ServeStorageAPI handles /api/storage/* routes (JSON API for disk operations).
 func (s *Server) ServeStorageAPI(w http.ResponseWriter, r *http.Request) {
 	s.storageAPIHandler(w, r)