feat(M5): P0 契约层 + 审批/应用设置下线

- types/homeworkV2.ts：V2 全量类型契约（五态/枚举/矩阵/版本/通知）
- teacherHomework/studentHomework/notification 三客户端（28 端点）
- §6 审批功能下线：删 ApprovalList/ApprovalSetting/ApprovalFlowEditor，
  types/api/menu/menuRoute/App/mock 同步清理，DROPPED_MOD_IDS={5,6}
- §7 应用设置下线：删 HomeworkSetting/TypeSetBox/UserCheckInput，
  SettingApi 与 dict/contacts 死代码清理，DROPPED_MOD_IDS 扩 {21}
- 新增 V2 组件：TeacherHomeworks（已发布+草稿箱）、ReviewModal（批阅弹窗）、
  AttachmentUpload（附件上传）——尚未挂路由，页面切换随后续阶段

src/components/layout.vue

@@ -134,13 +134,13 @@ const getMenuIcon = (item?: any): string => {
     const page: string = item?.page || "";
     if (page === "/list/new") return "icon-xiugaijl";
     if (page === "/list") return "icon-fasong";
+    if (page === "/submissions") return "icon-liebiao";
+    if (page === "/grade") return "icon-chengji";
     if (page === "/" || page === "/accept") return "icon-sjx";
     if (page === "/homeworklist") return "icon-liebiao";
-    if (page === "/approval") return "icon-shenpi";
-    if (page === "/approval-setting") return "icon-quanxian";
     if (page === "/stats") return "icon-tongji";
     if (page === "/setting") return "icon-shezhi";
-    if (page === "/stu/today" || page === "/par/kids") return "icon-sjx";
+    if (page === "/stu/today") return "icon-rili";
     if (page === "/stu/redo") return "icon-xiugaijl";
     switch (item?.modId ?? item?.id) {
         case 1: return "icon-xiugaijl";