feat(shared,tests): add error boundaries, lib utils, i18n messages, and integration tests

shared:

- Add class-filter, error-state, route-error, section-error-boundary, widget-boundary components

- Add ui/alert component

- Add constants directory

- Add breached-password, export-utils, permission-bitmap, rate-limit, resolve-action-error, route-permissions, route-resolver, type-guards lib

- Add i18n messages (en, zh-CN) for invitation-codes, parent, questions, rbac

tests:

- Add integration tests for elective

- Add tests/setup/empty-stub

scripts:

- Add update-md.cjs, tmp_append_en.ps1, tmp_merge_en.ps1 utilities

src/shared/i18n/messages/zh-CN/textbooks.json

@@ -164,6 +164,10 @@
   "grade": {
     "grade1": "一年级",
     "grade2": "二年级",
+    "grade3": "三年级",
+    "grade4": "四年级",
+    "grade5": "五年级",
+    "grade6": "六年级",
     "grade7": "七年级",
     "grade8": "八年级",
     "grade9": "九年级",
@@ -215,7 +219,9 @@
     "prerequisiteCreated": "前置依赖已添加",
     "prerequisiteCreateFailed": "添加前置依赖失败",
     "prerequisiteDeleted": "前置依赖已删除",
-    "prerequisiteDeleteFailed": "删除前置依赖失败"
+    "prerequisiteDeleteFailed": "删除前置依赖失败",
+    "notFound": "教材不存在或无权访问",
+    "noClassMasteryPermission": "无权查看班级掌握度数据"
   },
   "graph": {
     "viewMode": {
@@ -231,6 +237,7 @@
     },
     "detail": {
       "title": "知识点详情",
+      "close": "关闭",
       "noDescription": "暂无描述",
       "viewAllQuestions": "查看全部题目",
       "editPrerequisite": "编辑前置依赖",
@@ -246,6 +253,8 @@
       "totalQuestions": "总题数",
       "prerequisiteAdded": "前置依赖已添加",
       "prerequisiteRemoved": "前置依赖已移除",
+      "prerequisiteAddFailed": "添加前置依赖失败",
+      "prerequisiteRemoveFailed": "删除前置依赖失败",
       "cancel": "取消",
       "confirm": "确认",
       "saving": "保存中..."