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/app/(dashboard)/teacher/attendance/sheet/page.tsx

@@ -1,38 +1,33 @@
+import type { JSX } from "react"
 import { getTeacherClasses } from "@/modules/classes/data-access"
 import { getClassStudentsForAttendance } from "@/modules/attendance/data-access"
 import { AttendanceSheet } from "@/modules/attendance/components/attendance-sheet"
+import { getParam, type SearchParams } from "@/shared/lib/search-params"
 
 export const dynamic = "force-dynamic"
 
-type SearchParams = { [key: string]: string | string[] | undefined }
-
-const getParam = (params: SearchParams, key: string) => {
-  const v = params[key]
-  return Array.isArray(v) ? v[0] : v
-}
-
 export default async function AttendanceSheetPage({
   searchParams,
 }: {
   searchParams: Promise<SearchParams>
-}) {
+}): Promise<JSX.Element> {
   const sp = await searchParams
 
   const defaultClassId = getParam(sp, "classId")
   const defaultDate = getParam(sp, "date")
 
-  const classes = await getTeacherClasses()
+  const [classes, students] = await Promise.all([
+    getTeacherClasses(),
+    defaultClassId
+      ? getClassStudentsForAttendance(defaultClassId)
+      : Promise.resolve([] as Awaited<ReturnType<typeof getClassStudentsForAttendance>>),
+  ])
   const classOptions = classes.map((c) => ({ id: c.id, name: c.name }))
 
-  let students: Array<{ id: string; name: string; email: string }> = []
-  if (defaultClassId) {
-    students = await getClassStudentsForAttendance(defaultClassId)
-  }
-
   return (
     <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
       <div>
-        <h2 className="text-2xl font-bold tracking-tight">Take Attendance</h2>
+        <h1 className="text-2xl font-bold tracking-tight">Take Attendance</h1>
         <p className="text-muted-foreground">
           Select a class and date, then mark attendance for each student.
         </p>