feat: add dashboard overview health summary

atsf_server/router/api-router.go

@@ -109,6 +109,11 @@ func SetApiRouter(router *gin.Engine) {
 			configVersionRoute.POST("/publish", controller.PublishConfigVersion)
 			configVersionRoute.PUT("/:id/activate", controller.ActivateConfigVersion)
 		}
+		dashboardRoute := apiRouter.Group("/dashboard")
+		dashboardRoute.Use(middleware.AdminAuth())
+		{
+			dashboardRoute.GET("/overview", controller.GetDashboardOverview)
+		}
 		nodeRoute := apiRouter.Group("/nodes")
 		nodeRoute.Use(middleware.AdminAuth())
 		{

atsf_server/router/api_phase2_test.go

@@ -169,6 +169,13 @@ func TestPhase2AgentLifecycle(t *testing.T) {
 
 	createRouteAndPublishVersion(t, engine, adminToken)
 
+	dashboardResp := performJSONRequest(t, engine, adminToken, http.MethodGet, "/api/dashboard/overview", nil)
+	var dashboard service.DashboardOverviewView
+	decodeResponseData(t, dashboardResp, &dashboard)
+	if dashboard.Summary.TotalNodes != 0 {
+		t.Fatalf("expected empty dashboard node summary before node registration, got %+v", dashboard.Summary)
+	}
+
 	unauthorizedRequest := httptest.NewRequest(http.MethodPost, "/api/agent/nodes/register", bytes.NewReader([]byte(`{}`)))
 	unauthorizedRecorder := httptest.NewRecorder()
 	engine.ServeHTTP(unauthorizedRecorder, unauthorizedRequest)