feat: 新增备课模块并修复全模块 P0/P1/P2 缺陷

主要变更:

- 新增 lesson-preparation 模块: 备课编辑器、节点编辑、AI 建议、知识点选择、版本历史、作业发布

- 新增 shared 通用组件: charts/question-bank-filters/schedule-list/ui (chip-nav/filter-bar/page-header/stat-card/stat-item)

- 新增 student/admin 端 loading.tsx 与 error.tsx, 优化加载与错误态体验

- 新增 teacher/lesson-plans 页面 (列表/新建/编辑)

- 新增 drizzle 迁移 0002_tiny_lionheart 及 snapshot

- 新增 textbooks/schema.ts 与 exams/utils/normalize-structure.ts

- 修复 Tiptap v3 SSR hydration 崩溃 (rich-text-block immediatelyRender: false)

- 重构多模块 data-access/actions/组件, 修复权限校验与类型规范

- 同步架构文档 004/005 反映新增模块、导出、依赖关系

- 归档 bugs/* 测试报告与 e2e 测试脚本 (admin/parent/student/teacher web_test)

src/modules/lesson-preparation/hooks/use-lesson-plan-editor.ts

@@ -0,0 +1,170 @@
+"use client";
+
+import { create } from "zustand";
+import { createId } from "@paralleldrive/cuid2";
+import type {
+  Block,
+  BlockType,
+  LessonPlanDocument,
+  LessonPlanEdge,
+  LessonPlanNode,
+} from "../types";
+import { BLOCK_TYPE_LABELS } from "../constants";
+
+interface EditorState {
+  planId: string;
+  title: string;
+  doc: LessonPlanDocument;
+  isDirty: boolean;
+  isSaving: boolean;
+  lastSavedAt: number | null;
+  selectedNodeId: string | null;
+
+  setTitle: (title: string) => void;
+  setPlanId: (planId: string) => void;
+  hydrate: (planId: string, title: string, doc: LessonPlanDocument) => void;
+
+  addNode: (type: BlockType, position?: { x: number; y: number }) => string;
+  updateNode: (id: string, patch: Partial<Block>) => void;
+  updateNodePosition: (id: string, position: { x: number; y: number }) => void;
+  removeNode: (id: string) => void;
+
+  connect: (source: string, target: string) => void;
+  disconnect: (edgeId: string) => void;
+  setEdges: (edges: LessonPlanEdge[]) => void;
+
+  selectNode: (id: string | null) => void;
+
+  markSaved: () => void;
+  setSaving: (saving: boolean) => void;
+  replaceDoc: (doc: LessonPlanDocument) => void;
+}
+
+function reindex(nodes: LessonPlanNode[]): LessonPlanNode[] {
+  return nodes.map((n, i) => ({ ...n, order: i }));
+}
+
+function defaultData(type: BlockType): Block["data"] {
+  return type === "exercise"
+    ? { items: [], purpose: "class_practice", knowledgePointIds: [] }
+    : type === "text_study"
+      ? { sourceText: "", annotations: [], knowledgePointIds: [] }
+      : { html: "", knowledgePointIds: [] };
+}
+
+export const useLessonPlanEditor = create<EditorState>((set, get) => ({
+  planId: "",
+  title: "",
+  doc: { version: 2, nodes: [], edges: [] },
+  isDirty: false,
+  isSaving: false,
+  lastSavedAt: null,
+  selectedNodeId: null,
+
+  setTitle: (title) => set({ title, isDirty: true }),
+
+  setPlanId: (planId) => set({ planId }),
+
+  // 仅在 planId 变化时调用，避免覆盖用户编辑内容（修复 P1-3）
+  hydrate: (planId, title, doc) =>
+    set({
+      planId,
+      title,
+      doc,
+      isDirty: false,
+      lastSavedAt: Date.now(),
+      selectedNodeId: null,
+    }),
+
+  addNode: (type, position) => {
+    const id = createId();
+    const nodeCount = get().doc.nodes.length;
+    const node: LessonPlanNode = {
+      id,
+      type,
+      title: BLOCK_TYPE_LABELS[type],
+      data: defaultData(type),
+      order: nodeCount,
+      position: position ?? {
+        x: 80 + (nodeCount % 4) * 280,
+        y: 80 + Math.floor(nodeCount / 4) * 200,
+      },
+    };
+    set((s) => ({
+      doc: { ...s.doc, nodes: [...s.doc.nodes, node] },
+      isDirty: true,
+      selectedNodeId: id,
+    }));
+    return id;
+  },
+
+  updateNode: (id, patch) =>
+    set((s) => ({
+      doc: {
+        ...s.doc,
+        nodes: s.doc.nodes.map((n) =>
+          n.id === id ? { ...n, ...patch } : n,
+        ),
+      },
+      isDirty: true,
+    })),
+
+  updateNodePosition: (id, position) =>
+    set((s) => ({
+      doc: {
+        ...s.doc,
+        nodes: s.doc.nodes.map((n) =>
+          n.id === id ? { ...n, position } : n,
+        ),
+      },
+      isDirty: true,
+    })),
+
+  removeNode: (id) =>
+    set((s) => ({
+      doc: {
+        ...s.doc,
+        nodes: reindex(s.doc.nodes.filter((n) => n.id !== id)),
+        edges: s.doc.edges.filter(
+          (e) => e.source !== id && e.target !== id,
+        ),
+      },
+      isDirty: true,
+      selectedNodeId:
+        s.selectedNodeId === id ? null : s.selectedNodeId,
+    })),
+
+  connect: (source, target) =>
+    set((s) => {
+      // 避免重复连线
+      if (
+        s.doc.edges.some(
+          (e) => e.source === source && e.target === target,
+        )
+      )
+        return s;
+      const edge: LessonPlanEdge = {
+        id: `e_${source}_${target}_${createId().slice(0, 6)}`,
+        source,
+        target,
+      };
+      return { doc: { ...s.doc, edges: [...s.doc.edges, edge] }, isDirty: true };
+    }),
+
+  disconnect: (edgeId) =>
+    set((s) => ({
+      doc: {
+        ...s.doc,
+        edges: s.doc.edges.filter((e) => e.id !== edgeId),
+      },
+      isDirty: true,
+    })),
+
+  setEdges: (edges) => set((s) => ({ doc: { ...s.doc, edges }, isDirty: true })),
+
+  selectNode: (id) => set({ selectedNodeId: id }),
+
+  markSaved: () => set({ isDirty: false, lastSavedAt: Date.now() }),
+  setSaving: (saving) => set({ isSaving: saving }),
+  replaceDoc: (doc) => set({ doc, isDirty: false }),
+}));