feat(lesson-preparation): update paper-editor, detail-panel, AI node assist, i18n

- Update actions-ai.ts and curriculum-map-view.tsx

- Update detail-panel: detail-panel, detail-props, qa-editor

- Update paper-editor: inline-node, inline-qa-dialog, paper-context-menu,

  paper-editor, textbook-tiptap-editor

- Update hooks/editor-slice.ts and lib/i18n-errors.ts

- Add hooks/use-node-ai-assist.ts and lib/ai-node-assist.ts

- Update en/zh-CN lesson-preparation i18n messages

src/modules/lesson-preparation/hooks/editor-slice.ts

@@ -3,7 +3,9 @@ import { createId } from "@paralleldrive/cuid2";
 import type {
   AnchorType,
   Block,
+  BlockData,
   BlockType,
+  InteractionBlockData,
   LessonPlanDocument,
   LessonPlanNode,
   NodeAnchor,
@@ -13,6 +15,23 @@ import type {
 import { defaultDataForType } from "../lib/document-migration";
 import type { EditorState } from "./use-lesson-plan-editor";
 
+/**
+ * V4：深拷贝 BlockData，为 interaction 节点的 turns 重新生成 id（避免 id 冲突）。
+ * 其他类型直接结构化克隆（JSON 序列化足够，数据全是 POJO）。
+ */
+function cloneBlockData(data: BlockData, type: BlockType): BlockData {
+  if (type === "interaction") {
+    const d = data as InteractionBlockData;
+    return {
+      designIntent: d.designIntent,
+      knowledgePointIds: [...d.knowledgePointIds],
+      turns: d.turns.map((t) => ({ ...t, id: createId() })),
+    };
+  }
+  // 其他类型：JSON 深拷贝（数据全是 POJO，无函数/Date/Symbol）
+  return JSON.parse(JSON.stringify(data)) as BlockData;
+}
+
 export interface EditorSlice {
   planId: string;
   title: string;
@@ -22,6 +41,8 @@ export interface EditorSlice {
   addNode: (type: BlockType, position?: { x: number; y: number }, title?: string) => string;
   updateNode: (id: string, patch: Omit<Partial<Block>, "type">) => void;
   removeNode: (id: string) => void;
+  /** V4：复制节点（深拷贝数据 + 新 id + 标题加"副本" + order 置末） */
+  duplicateNode: (id: string) => string | null;
   updateTextbookContent: (data: Partial<TextbookContentNodeData>) => void;
   getTextbookContentNode: () => TextbookContentNode | undefined;
   /**
@@ -141,6 +162,37 @@ export const createEditorSlice: StateCreator<
     });
   },
 
+  duplicateNode: (id) => {
+    const state = get();
+    const src = state.doc.nodes.find(
+      (n): n is LessonPlanNode => n.id === id && n.type !== "textbook_content",
+    );
+    if (!src) return null;
+    state.pushHistory();
+    const newId = createId();
+    const teachingNodes = state.doc.nodes.filter(
+      (n): n is LessonPlanNode => n.type !== "textbook_content",
+    );
+    // 深拷贝 data（避免引用共享）；interaction 节点的 turns 内 id 重新生成
+    const clonedData = cloneBlockData(src.data, src.type);
+    const newNode: LessonPlanNode = {
+      id: newId,
+      type: src.type,
+      title: `${src.title}（副本）`,
+      data: clonedData,
+      order: teachingNodes.length,
+      position: { x: 0, y: 0 },
+      stage: src.stage,
+      differentiation: src.differentiation,
+    };
+    set((s) => ({
+      doc: { ...s.doc, nodes: [...s.doc.nodes, newNode] },
+      isDirty: true,
+      selectedNodeId: newId,
+    }));
+    return newId;
+  },
+
   updateTextbookContent: (data) => {
     get().pushHistory(); // V5-2：撤销/重做
     set((s) => ({