Add Overview page with kind-grouped node cards and RAM/disk metrics.

Batch-fetch action widgets so the dashboard can show free/total memory and disk usage without N+1 requests.

service/internal/api/action_widgets_handlers.go

@@ -24,3 +24,51 @@ func (app *App) actionWidgetsListHandler(writer http.ResponseWriter, request *ht
 		Widgets: settings.WidgetsForNode(store, node.ID),
 	})
 }
+
+// actionWidgetsListAllHandler returns widget snapshots for every node the caller can access.
+func (app *App) actionWidgetsListAllHandler(writer http.ResponseWriter, request *http.Request) {
+	if err := app.authorizeNodesRead(request); err != nil {
+		writeJSON(writer, http.StatusForbidden, apiErrorResponse{Error: err.Error()})
+		return
+	}
+
+	user, ok := UserFromContext(request.Context())
+	if !ok {
+		writeJSON(writer, http.StatusUnauthorized, apiErrorResponse{Error: "authentication required"})
+		return
+	}
+
+	settingsPayload, err := loadSettingsOrDefault(app.ConfigDir)
+	if err != nil {
+		writeJSON(writer, http.StatusInternalServerError, apiErrorResponse{Error: err.Error()})
+		return
+	}
+
+	nodesStore, err := settings.LoadNodesOrEmpty(app.ConfigDir)
+	if err != nil {
+		writeJSON(writer, http.StatusInternalServerError, apiErrorResponse{Error: err.Error()})
+		return
+	}
+
+	accessibleNodeIDs := make(map[string]struct{}, len(nodesStore.Nodes))
+	for _, node := range nodesStore.Nodes {
+		if userCanAccessNode(user, settingsPayload.Groups, node) {
+			accessibleNodeIDs[node.ID] = struct{}{}
+		}
+	}
+
+	widgetStore, err := settings.LoadActionWidgetsOrEmpty(app.ConfigDir)
+	if err != nil {
+		writeJSON(writer, http.StatusInternalServerError, apiErrorResponse{Error: err.Error()})
+		return
+	}
+
+	filtered := make([]settings.ActionWidgetSnapshot, 0)
+	for _, widget := range widgetStore.Widgets {
+		if _, ok := accessibleNodeIDs[widget.NodeID]; ok {
+			filtered = append(filtered, widget)
+		}
+	}
+
+	writeJSON(writer, http.StatusOK, actionWidgetsResponse{Widgets: filtered})
+}