feat(web): 添加 usePermission hook + AuthButton/AuthGuard 声明式权限组件

apps/web/src/hooks/usePermission.ts

@@ -0,0 +1,6 @@
+import { useAuthStore } from '../stores/auth';
+
+export function usePermission(code: string): { hasPermission: boolean } {
+  const permissions = useAuthStore((s) => s.permissions);
+  return { hasPermission: permissions.includes(code) };
+}