feat(lesson-preparation): add AI evaluation, analytics, attachments, calendar, comments, review, substitutes, formative, and version diff

- Add actions-ai-evaluation, actions-analytics, actions-attachments, actions-calendar, actions-comments, actions-formative, actions-questions, actions-review, actions-substitutes

- Add corresponding data-access layers for each new action module

- Add calendar-view, curriculum-map-view, version-diff-viewer components

- Add editor-slice, selection-slice, version-slice hooks for state management

- Add document-diff and scope-check lib utilities

- Add default-question-service and external-questions-bridge services

src/modules/lesson-preparation/lib/document-diff.ts

@@ -0,0 +1,167 @@
+/**
+ * M11 版本 diff 预览 - 纯函数模块
+ *
+ * 基于字符串差异对比算法，输出可用于 React 渲染的 diff 段落。
+ * 实现思路：
+ * - 将 LessonPlanDocument 序列化为可读文本（节点列表 + 标题）
+ * - 使用简化的 LCS 算法对比两段文本
+ * - 输出 added/removed/unchanged 三种段落
+ *
+ * 此模块仅做纯计算，UI 渲染由 version-diff-viewer.tsx 负责。
+ */
+
+import type { LessonPlanDocument } from "../types";
+
+/** diff 段落类型 */
+export type DiffSegmentType = "added" | "removed" | "unchanged";
+
+/** diff 单个段落 */
+export interface DiffSegment {
+  type: DiffSegmentType;
+  content: string;
+  lineNumber?: number;
+}
+
+/**
+ * 将 LessonPlanDocument 序列化为可读文本（用于 diff 比对）
+ * 每行一个节点，包含节点类型、标题、关键字段摘要
+ */
+export function serializeDocumentToText(doc: LessonPlanDocument): string {
+  const lines: string[] = [];
+  lines.push(`Version: ${doc.version}`);
+  lines.push(`TextbookNodeId: ${doc.textbookContentNodeId}`);
+  lines.push(`Nodes (${doc.nodes.length}):`);
+
+  for (const node of doc.nodes) {
+    const summary = summarizeNode(node);
+    lines.push(`  [${node.type}] ${node.title ?? "(no title)"} - ${summary}`);
+  }
+
+  lines.push(`Edges (${doc.edges.length}):`);
+  for (const edge of doc.edges) {
+    lines.push(`  ${edge.source} → ${edge.target} (${"type" in edge ? edge.type : "unknown"})`);
+  }
+
+  lines.push(`Anchors (${doc.anchors.length}):`);
+  for (const anchor of doc.anchors) {
+    lines.push(
+      `  ${anchor.id}: node=${anchor.nodeId} type=${anchor.type} start=${anchor.start}${anchor.end !== undefined ? ` end=${anchor.end}` : ""}`,
+    );
+  }
+
+  return lines.join("\n");
+}
+
+/**
+ * 节点摘要（提取关键字段以便 diff 可读）
+ */
+function summarizeNode(node: { data?: unknown; type: string }): string {
+  if (!node.data || typeof node.data !== "object") return "";
+  const data = node.data as Record<string, unknown>;
+  const fields: string[] = [];
+  for (const key of Object.keys(data).slice(0, 5)) {
+    const value = data[key];
+    if (typeof value === "string") {
+      fields.push(`${key}="${value.slice(0, 60)}"`);
+    } else if (Array.isArray(value)) {
+      fields.push(`${key}=[${value.length} items]`);
+    } else if (typeof value === "number" || typeof value === "boolean") {
+      fields.push(`${key}=${value}`);
+    }
+  }
+  return fields.join(", ");
+}
+
+/**
+ * 简化 LCS diff 算法
+ * 输入两段文本，输出 diff 段落数组
+ *
+ * 时间复杂度 O(n*m)，对于教案文档（通常 < 500 行）可接受。
+ * 对于更长文本可换用 diff-match-patch 库。
+ */
+export function computeTextDiff(
+  oldText: string,
+  newText: string,
+): DiffSegment[] {
+  const oldLines = oldText.split("\n");
+  const newLines = newText.split("\n");
+
+  // 构建 LCS 矩阵
+  const m = oldLines.length;
+  const n = newLines.length;
+  const lcs: number[][] = Array.from({ length: m + 1 }, () =>
+    new Array<number>(n + 1).fill(0),
+  );
+
+  for (let i = 1; i <= m; i++) {
+    for (let j = 1; j <= n; j++) {
+      if (oldLines[i - 1] === newLines[j - 1]) {
+        lcs[i][j] = lcs[i - 1][j - 1] + 1;
+      } else {
+        lcs[i][j] = Math.max(lcs[i - 1][j], lcs[i][j - 1]);
+      }
+    }
+  }
+
+  // 回溯生成 diff 段落
+  const segments: DiffSegment[] = [];
+  let i = m;
+  let j = n;
+  while (i > 0 || j > 0) {
+    if (i > 0 && j > 0 && oldLines[i - 1] === newLines[j - 1]) {
+      segments.unshift({
+        type: "unchanged",
+        content: oldLines[i - 1]!,
+        lineNumber: i,
+      });
+      i--;
+      j--;
+    } else if (j > 0 && (i === 0 || lcs[i][j - 1] >= lcs[i - 1][j])) {
+      segments.unshift({
+        type: "added",
+        content: newLines[j - 1]!,
+        lineNumber: j,
+      });
+      j--;
+    } else if (i > 0) {
+      segments.unshift({
+        type: "removed",
+        content: oldLines[i - 1]!,
+        lineNumber: i,
+      });
+      i--;
+    }
+  }
+
+  return segments;
+}
+
+/**
+ * 计算两个课案文档的 diff
+ */
+export function computeDocumentDiff(
+  oldDoc: LessonPlanDocument,
+  newDoc: LessonPlanDocument,
+): DiffSegment[] {
+  return computeTextDiff(
+    serializeDocumentToText(oldDoc),
+    serializeDocumentToText(newDoc),
+  );
+}
+
+/**
+ * 统计 diff 摘要
+ */
+export function summarizeDiff(
+  segments: DiffSegment[],
+): { added: number; removed: number; unchanged: number; total: number } {
+  let added = 0;
+  let removed = 0;
+  let unchanged = 0;
+  for (const seg of segments) {
+    if (seg.type === "added") added++;
+    else if (seg.type === "removed") removed++;
+    else unchanged++;
+  }
+  return { added, removed, unchanged, total: segments.length };
+}