fix(textbooks): 规范核查修复 — 安全漏洞+功能缺失+i18n+类型安全

安全：createPrerequisiteAction 补充 prerequisiteKpId 归属校验；deletePrerequisiteAction 补充双知识点归属校验，防止跨教材越权。

功能：实现图谱添加/删除前置依赖（Dialog + Select 选择知识点 + 调用 Server Action + 自动刷新图谱），替换原 no-op 回调。

i18n：修复 8 处硬编码英文字符串（textbook-reader/chapter-sidebar-list/textbook-card/textbook-form-dialog/textbook-settings-dialog/create-chapter-dialog/teacher-textbook-reader），新增 saveFailed/createFailed/updateFailed/deleteFailed/questionCreatorDefaultContent 等 key。

类型安全：graph-prerequisite-edge.tsx 使用 GraphEdgeData 类型经 unknown 安全转换，替代裸 as 断言。

规范：analytics.tsx 移动 use client 指令到文件第一行；同步架构文档 005 JSON 类型定义（GraphNodeData/GraphEdgeData/MasteryLevel）。

验证：教材模块 lint 零错误、tsc 零错误、193 个单元测试全部通过。

src/shared/i18n/messages/en/textbooks.json

@@ -48,6 +48,11 @@
     "cancel": "Cancel",
     "save": "Save",
     "saving": "Saving...",
+    "saveFailed": "Failed to save",
+    "createFailed": "Failed to create",
+    "updateFailed": "Failed to update",
+    "deleteFailed": "Failed to delete",
+    "questionCreatorDefaultContent": "Please explain the knowledge point: {name}",
     "addKnowledgePoint": "Add Knowledge Point",
     "clickToViewKp": "Click to view knowledge point details",
     "noChapters": "No chapters",
@@ -228,12 +233,20 @@
       "viewAllQuestions": "View all questions",
       "editPrerequisite": "Edit prerequisites",
       "addPrerequisite": "Add prerequisite",
+      "addPrerequisiteTitle": "Add Prerequisite Knowledge Point",
+      "addPrerequisiteDesc": "Select a knowledge point as the prerequisite of the current one.",
+      "selectPrerequisite": "Select a prerequisite knowledge point",
       "removePrerequisite": "Remove",
       "noPrerequisites": "No prerequisite knowledge points",
       "noSuccessors": "No successor knowledge points",
       "masteryNotAssessed": "Not assessed",
       "correctRate": "Correct rate",
-      "totalQuestions": "Total questions"
+      "totalQuestions": "Total questions",
+      "prerequisiteAdded": "Prerequisite added",
+      "prerequisiteRemoved": "Prerequisite removed",
+      "cancel": "Cancel",
+      "confirm": "Confirm",
+      "saving": "Saving..."
     },
     "toolbar": {
       "search": "Search knowledge points",

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

@@ -48,6 +48,11 @@
     "cancel": "取消",
     "save": "保存",
     "saving": "保存中...",
+    "saveFailed": "保存失败",
+    "createFailed": "创建失败",
+    "updateFailed": "更新失败",
+    "deleteFailed": "删除失败",
+    "questionCreatorDefaultContent": "请讲解知识点：{name}",
     "addKnowledgePoint": "添加知识点",
     "clickToViewKp": "点击查看知识点详情",
     "noChapters": "暂无章节",
@@ -228,12 +233,20 @@
       "viewAllQuestions": "查看全部题目",
       "editPrerequisite": "编辑前置依赖",
       "addPrerequisite": "添加前置",
+      "addPrerequisiteTitle": "添加前置知识点",
+      "addPrerequisiteDesc": "选择一个知识点作为当前知识点的前置依赖。",
+      "selectPrerequisite": "请选择前置知识点",
       "removePrerequisite": "移除",
       "noPrerequisites": "暂无前置知识点",
       "noSuccessors": "暂无后置知识点",
       "masteryNotAssessed": "未测评",
       "correctRate": "正确率",
-      "totalQuestions": "总题数"
+      "totalQuestions": "总题数",
+      "prerequisiteAdded": "前置依赖已添加",
+      "prerequisiteRemoved": "前置依赖已移除",
+      "cancel": "取消",
+      "confirm": "确认",
+      "saving": "保存中..."
     },
     "toolbar": {
       "search": "搜索知识点",