Scaffold @forte/admin package with React, Vite, shadcn/ui, TanStack Router

Sets up the admin frontend with login page, auth guard, API client, Zustand
auth store, and all shadcn/ui components. Vite proxies /v1 to backend in dev.

packages/admin/src/api/auth.ts

@@ -0,0 +1,16 @@
+import { api } from '@/lib/api-client'
+
+interface LoginResponse {
+  token: string
+  user: {
+    id: string
+    email: string
+    firstName: string
+    lastName: string
+    role: string
+  }
+}
+
+export async function login(email: string, password: string): Promise<LoginResponse> {
+  return api.post<LoginResponse>('/v1/auth/login', { email, password })
+}