feat(admin): batch update user limits

frontend/src/types/index.ts

@@ -1734,6 +1734,7 @@ export interface UpdateUserRequest {
   role?: 'admin' | 'user'
   balance?: number
   concurrency?: number
+  rpm_limit?: number
   status?: 'active' | 'disabled'
   allowed_groups?: number[] | null
   // 用户专属分组倍率配置 (group_id -> rate_multiplier | null)