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/components/node-editor.tsx

@@ -0,0 +1,155 @@
+"use client";
+
+import { useCallback, useMemo } from "react";
+import {
+  ReactFlow,
+  Background,
+  Controls,
+  MiniMap,
+  type Node,
+  type Edge,
+  type NodeChange,
+  type EdgeChange,
+  type Connection,
+  applyNodeChanges,
+  applyEdgeChanges,
+  BackgroundVariant,
+} from "@xyflow/react";
+import "@xyflow/react/dist/style.css";
+import { useLessonPlanEditor } from "../hooks/use-lesson-plan-editor";
+import { LessonNode } from "./nodes/lesson-node";
+import type { LessonPlanNode } from "../types";
+
+const nodeTypes = { lesson: LessonNode };
+
+interface Props {
+  textbookId?: string;
+  chapterId?: string;
+  classes?: { id: string; name: string }[];
+}
+
+export function NodeEditor({ textbookId, chapterId, classes }: Props) {
+  const { doc, selectedNodeId, updateNodePosition, removeNode, connect, selectNode, setEdges } =
+    useLessonPlanEditor();
+
+  // 我们的 nodes → React Flow nodes
+  const rfNodes: Node[] = useMemo(
+    () =>
+      doc.nodes.map((n) => ({
+        id: n.id,
+        type: "lesson",
+        position: n.position,
+        data: n as unknown as Record<string, unknown>,
+        selected: n.id === selectedNodeId,
+      })),
+    [doc.nodes, selectedNodeId],
+  );
+
+  // edges 直接兼容
+  const rfEdges: Edge[] = useMemo(
+    () =>
+      doc.edges.map((e) => ({
+        ...e,
+        animated: true,
+        style: { stroke: "#1976d2", strokeWidth: 2 },
+      })),
+    [doc.edges],
+  );
+
+  const onNodesChange = useCallback(
+    (changes: NodeChange[]) => {
+      changes.forEach((change) => {
+        if (change.type === "position" && change.position) {
+          updateNodePosition(change.id, change.position);
+        } else if (change.type === "remove") {
+          removeNode(change.id);
+        } else if (change.type === "select") {
+          selectNode(change.selected ? change.id : null);
+        }
+      });
+      // applyNodeChanges 用于内部状态同步，但我们用 zustand 管理，这里不需要
+      void applyNodeChanges;
+    },
+    [updateNodePosition, removeNode, selectNode],
+  );
+
+  const onConnect = useCallback(
+    (conn: Connection) => {
+      if (conn.source && conn.target) {
+        connect(conn.source, conn.target);
+      }
+    },
+    [connect],
+  );
+
+  // 同步 edges 变化（如拖拽重连）
+  const onEdgesChangeSync = useCallback(
+    (changes: EdgeChange[]) => {
+      // 简单处理：删除时调用 disconnect
+      const nextEdges = applyEdgeChanges(changes, rfEdges);
+      const ourEdges = nextEdges.map((e) => ({
+        id: e.id,
+        source: e.source,
+        target: e.target,
+        sourceHandle: e.sourceHandle ?? null,
+        targetHandle: e.targetHandle ?? null,
+      }));
+      setEdges(ourEdges);
+    },
+    [rfEdges, setEdges],
+  );
+
+  return (
+    <div className="w-full h-full">
+      <ReactFlow
+        nodes={rfNodes}
+        edges={rfEdges}
+        nodeTypes={nodeTypes}
+        onNodesChange={onNodesChange}
+        onEdgesChange={onEdgesChangeSync}
+        onConnect={onConnect}
+        onNodeClick={(_, node) => selectNode(node.id)}
+        onPaneClick={() => selectNode(null)}
+        fitView
+        fitViewOptions={{ padding: 0.2, maxZoom: 1.2 }}
+        defaultEdgeOptions={{
+          animated: true,
+          style: { stroke: "#1976d2", strokeWidth: 2 },
+        }}
+        proOptions={{ hideAttribution: true }}
+        className="bg-surface-container-low"
+      >
+        <Background
+          variant={BackgroundVariant.Dots}
+          gap={20}
+          size={1}
+          color="#ccc"
+        />
+        <Controls className="!bg-surface !border-outline-variant" />
+        <MiniMap
+          className="!bg-surface !border-outline-variant"
+          nodeColor={(n) => {
+            const data = n.data as unknown as LessonPlanNode;
+            const colors: Record<string, string> = {
+              objective: "#4caf50",
+              key_point: "#f44336",
+              import: "#2196f3",
+              new_teaching: "#9c27b0",
+              consolidation: "#ff9800",
+              summary: "#607d8b",
+              homework: "#795548",
+              blackboard: "#009688",
+              text_study: "#3f51b5",
+              exercise: "#e91e63",
+              rich_text: "#9e9e9e",
+              reflection: "#cddc39",
+            };
+            return colors[data.type] ?? "#9e9e9e";
+          }}
+        />
+      </ReactFlow>
+      {/* 隐藏的 props 传递，避免 unused 警告 */}
+      <span className="hidden" data-textbook={textbookId} data-chapter={chapterId} data-classes={classes?.length} />
+    </div>
+  );
+}