feat : add frontend dashboard types and service

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

frontend/services/dashboard.ts

@@ -0,0 +1,13 @@
+import type { DashboardResponse, EnvironmentHealth } from './dto/dashboard'
+
+export function getDashboard(): Promise<DashboardResponse> {
+    return useApi().get<DashboardResponse>('/dashboard', undefined, {
+        toast: false,
+    })
+}
+
+export function getEnvironmentHealth(envId: number): Promise<EnvironmentHealth> {
+    return useApi().get<EnvironmentHealth>(`/environments/${envId}/health`, undefined, {
+        toast: false,
+    })
+}