feat(attendance,elective): 实现所有 P2 长期改进项

P2 修复（来自审计报告）：
- 2.4.4: Server Action 错误消息 i18n 化（attendance/elective 全部 Action）
- 2.5.3: 抽取 AttendancePageLayout 组件复用（admin/teacher 页面）
- 2.5.4: 抽取 ElectivePageLayout 组件复用（admin/teacher 列表页）
- 2.6.3: 考勤月历键盘导航（tabIndex + 方向键 + Home/End + role=grid）
- 2.8.2: getStudentAttendanceSummary 分页优化（SQL 聚合统计 + LIMIT 分页）
- 2.8.3: resolveCourseDisplayNames 缓存优化（React cache 去重）
- 2.1.4: elective data-access 跨模块依赖接口抽象（resolvers.ts 可注入）

P2 建议项：
- 选课时间冲突检测（parseSchedule + isScheduleConflict 纯函数 + checkScheduleConflict）
- 学分上限校验（MAX_CREDIT_PER_TERM + checkCreditLimit）
- 考勤/选课数据导出 Excel（export.ts + API 路由扩展）

新增文件：
- src/modules/attendance/components/attendance-page-layout.tsx
- src/modules/elective/components/elective-page-layout.tsx
- src/modules/elective/resolvers.ts
- src/modules/attendance/export.ts
- src/modules/elective/export.ts

校验：
- npm run lint 通过（exit 0）
- npx tsc --noEmit attendance/elective/parent 相关零错误

src/app/(dashboard)/admin/attendance/page.tsx

@@ -14,6 +14,7 @@ import { getAttendanceRecords, getAttendanceStats } from "@/modules/attendance/d
 import { AttendanceFilters } from "@/modules/attendance/components/attendance-filters"
 import { AttendanceStatsCards } from "@/modules/attendance/components/attendance-stats-cards"
 import { AttendanceRecordList } from "@/modules/attendance/components/attendance-record-list"
+import { AttendancePageLayout } from "@/modules/attendance/components/attendance-page-layout"
 import type { AttendanceStatus } from "@/modules/attendance/types"
 
 export const dynamic = "force-dynamic"
@@ -55,25 +56,27 @@ export default async function AdminAttendancePage({
     date: date && date.length > 0 ? date : undefined,
   })
 
-  return (
-    <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
-      <div className="flex items-center justify-between space-y-2">
-        <div>
-          <h2 className="text-2xl font-bold tracking-tight">{t("title.adminOverview")}</h2>
-          <p className="text-muted-foreground">{t("description.adminOverview")}</p>
-        </div>
-        <Button asChild variant="outline">
-          <Link href="/teacher/attendance/stats">
-            <BarChart3 className="mr-2 h-4 w-4" />
-            {t("actions.stats")}
-          </Link>
-        </Button>
+  const header = (
+    <div className="flex items-center justify-between space-y-2">
+      <div>
+        <h2 className="text-2xl font-bold tracking-tight">{t("title.adminOverview")}</h2>
+        <p className="text-muted-foreground">{t("description.adminOverview")}</p>
       </div>
+      <Button asChild variant="outline">
+        <Link href="/teacher/attendance/stats">
+          <BarChart3 className="mr-2 h-4 w-4" />
+          {t("actions.stats")}
+        </Link>
+      </Button>
+    </div>
+  )
 
-      <AttendanceStatsCards stats={stats} />
-
-      <AttendanceFilters classes={classOptions} />
-
+  return (
+    <AttendancePageLayout
+      header={header}
+      stats={<AttendanceStatsCards stats={stats} />}
+      filters={<AttendanceFilters classes={classOptions} />}
+    >
       {result.items.length === 0 && !classId && !status && !date ? (
         <EmptyState
           title={t("list.empty")}
@@ -83,6 +86,6 @@ export default async function AdminAttendancePage({
       ) : (
         <AttendanceRecordList records={result.items} />
       )}
-    </div>
+    </AttendancePageLayout>
   )
 }

src/app/(dashboard)/admin/elective/page.tsx

@@ -4,6 +4,7 @@ import { getTranslations } from "next-intl/server"
 
 import { getElectiveCourses } from "@/modules/elective/data-access"
 import { ElectiveCourseList } from "@/modules/elective/components/elective-course-list"
+import { ElectivePageLayout } from "@/modules/elective/components/elective-page-layout"
 import { getSearchParam, type SearchParams } from "@/shared/lib/utils"
 import type { ElectiveCourseStatus } from "@/modules/elective/types"
 
@@ -24,20 +25,23 @@ export default async function AdminElectivePage({
 
   const courses = await getElectiveCourses({ status })
 
+  const header = (
+    <div className="space-y-1">
+      <h2 className="text-2xl font-bold tracking-tight">{t("title.adminList")}</h2>
+      <p className="text-muted-foreground">
+        {t("description.adminList")}
+      </p>
+    </div>
+  )
+
   return (
-    <div className="flex h-full flex-col space-y-8 p-8">
-      <div className="space-y-1">
-        <h2 className="text-2xl font-bold tracking-tight">{t("title.adminList")}</h2>
-        <p className="text-muted-foreground">
-          {t("description.adminList")}
-        </p>
-      </div>
+    <ElectivePageLayout header={header}>
       <ElectiveCourseList
         courses={courses}
         canManage
         createHref="/admin/elective/create"
         editBaseHref="/admin/elective"
       />
-    </div>
+    </ElectivePageLayout>
   )
 }

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

@@ -11,6 +11,7 @@ import { getTeacherClasses } from "@/modules/classes/data-access"
 import { getAttendanceRecords } from "@/modules/attendance/data-access"
 import { AttendanceFilters } from "@/modules/attendance/components/attendance-filters"
 import { AttendanceRecordList } from "@/modules/attendance/components/attendance-record-list"
+import { AttendancePageLayout } from "@/modules/attendance/components/attendance-page-layout"
 import type { AttendanceStatus } from "@/modules/attendance/types"
 
 export const dynamic = "force-dynamic"
@@ -62,31 +63,34 @@ export default async function TeacherAttendancePage({
   const pagedRecords = paginate(result.items, currentPage, PAGE_SIZE)
   const hasFilters = Boolean(classId || status || date)
 
-  return (
-    <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
-      <div className="flex items-center justify-between space-y-2">
-        <div>
-          <h1 className="text-2xl font-bold tracking-tight">{t("title.teacherRecords")}</h1>
-          <p className="text-muted-foreground">{t("description.teacherRecords")}</p>
-        </div>
-        <div className="flex items-center gap-2">
-          <Button asChild variant="outline">
-            <Link href="/teacher/attendance/stats">
-              <BarChart3 className="mr-2 h-4 w-4" aria-hidden="true" />
-              {t("actions.stats")}
-            </Link>
-          </Button>
-          <Button asChild>
-            <Link href="/teacher/attendance/sheet">
-              <PlusCircle className="mr-2 h-4 w-4" aria-hidden="true" />
-              {t("actions.record")}
-            </Link>
-          </Button>
-        </div>
+  const header = (
+    <div className="flex items-center justify-between space-y-2">
+      <div>
+        <h1 className="text-2xl font-bold tracking-tight">{t("title.teacherRecords")}</h1>
+        <p className="text-muted-foreground">{t("description.teacherRecords")}</p>
       </div>
+      <div className="flex items-center gap-2">
+        <Button asChild variant="outline">
+          <Link href="/teacher/attendance/stats">
+            <BarChart3 className="mr-2 h-4 w-4" aria-hidden="true" />
+            {t("actions.stats")}
+          </Link>
+        </Button>
+        <Button asChild>
+          <Link href="/teacher/attendance/sheet">
+            <PlusCircle className="mr-2 h-4 w-4" aria-hidden="true" />
+            {t("actions.record")}
+          </Link>
+        </Button>
+      </div>
+    </div>
+  )
 
-      <AttendanceFilters classes={classOptions} />
-
+  return (
+    <AttendancePageLayout
+      header={header}
+      filters={<AttendanceFilters classes={classOptions} />}
+    >
       {result.items.length === 0 && !hasFilters ? (
         <EmptyState
           title={t("list.empty")}
@@ -113,6 +117,6 @@ export default async function TeacherAttendancePage({
           ) : null}
         </div>
       )}
-    </div>
+    </AttendancePageLayout>
   )
 }

src/app/(dashboard)/teacher/elective/page.tsx

@@ -1,9 +1,11 @@
 import type { JSX } from "react"
 import { getTranslations } from "next-intl/server"
-import { getAuthContext } from "@/shared/lib/auth-guard"
+import { requirePermission } from "@/shared/lib/auth-guard"
+import { Permissions } from "@/shared/types/permissions"
 import { getParam, type SearchParams } from "@/shared/lib/search-params"
 import { getElectiveCourses } from "@/modules/elective/data-access"
 import { ElectiveCourseList } from "@/modules/elective/components/elective-course-list"
+import { ElectivePageLayout } from "@/modules/elective/components/elective-page-layout"
 import type { ElectiveCourseStatus } from "@/modules/elective/types"
 
 export const dynamic = "force-dynamic"
@@ -25,7 +27,7 @@ export default async function TeacherElectivePage({
   searchParams: Promise<SearchParams>
 }): Promise<JSX.Element> {
   const t = await getTranslations("elective")
-  const ctx = await getAuthContext()
+  const ctx = await requirePermission(Permissions.ELECTIVE_READ)
   const teacherId = ctx.userId
 
   const sp = await searchParams
@@ -36,18 +38,21 @@ export default async function TeacherElectivePage({
     ? await getElectiveCourses({ teacherId, status })
     : []
 
+  const header = (
+    <div className="space-y-1">
+      <h1 className="text-2xl font-bold tracking-tight">{t("title.teacher")}</h1>
+      <p className="text-muted-foreground">{t("description.teacher")}</p>
+    </div>
+  )
+
   return (
-    <div className="flex h-full flex-col space-y-8 p-8">
-      <div className="space-y-1">
-        <h1 className="text-2xl font-bold tracking-tight">{t("title.teacher")}</h1>
-        <p className="text-muted-foreground">{t("description.teacher")}</p>
-      </div>
+    <ElectivePageLayout header={header}>
       <ElectiveCourseList
         courses={courses}
         canManage
         createHref="/admin/elective/create"
         editBaseHref="/admin/elective"
       />
-    </div>
+    </ElectivePageLayout>
   )
 }

src/app/api/export/route.ts

@@ -5,6 +5,8 @@ import { Permissions } from "@/shared/types/permissions"
 import { formatDateForFile } from "@/shared/lib/utils"
 import { exportUsersToExcel } from "@/modules/users/import-export"
 import { exportGradeRecordsToExcel } from "@/modules/grades/export"
+import { exportAttendanceRecordsToExcel } from "@/modules/attendance/export"
+import { exportElectiveCoursesToExcel, exportCourseSelectionsToExcel } from "@/modules/elective/export"
 import {
   exportAuditLogsAction,
   exportDataChangeLogsAction,
@@ -13,10 +15,25 @@ import {
 
 export const dynamic = "force-dynamic"
 
-type ExportType = "grades" | "users" | "attendance" | "audit" | "login" | "dataChange"
+type ExportType =
+  | "grades"
+  | "users"
+  | "attendance"
+  | "electiveCourses"
+  | "courseSelections"
+  | "audit"
+  | "login"
+  | "dataChange"
 
 const isExportType = (v: string): v is ExportType =>
-  v === "grades" || v === "users" || v === "attendance" || v === "audit" || v === "login" || v === "dataChange"
+  v === "grades" ||
+  v === "users" ||
+  v === "attendance" ||
+  v === "electiveCourses" ||
+  v === "courseSelections" ||
+  v === "audit" ||
+  v === "login" ||
+  v === "dataChange"
 
 export async function POST(req: Request) {
   try {
@@ -53,6 +70,62 @@ export async function POST(req: Request) {
         role: params.role ? String(params.role) : undefined,
       })
       filename = `users_export_${formatDateForFile()}.xlsx`
+    } else if (type === "attendance") {
+      // 考勤导出需要 ATTENDANCE_READ 权限
+      try {
+        await requirePermission(Permissions.ATTENDANCE_READ)
+      } catch (e) {
+        if (e instanceof PermissionDeniedError) {
+          return NextResponse.json(
+            { success: false, message: e.message },
+            { status: 403 }
+          )
+        }
+        throw e
+      }
+      buffer = await exportAttendanceRecordsToExcel({
+        scope: ctx.dataScope,
+        currentUserId: ctx.userId,
+        classId: params.classId ? String(params.classId) : undefined,
+        status: params.status ? String(params.status) : undefined,
+        date: params.date ? String(params.date) : undefined,
+      })
+      filename = `attendance_export_${formatDateForFile()}.xlsx`
+    } else if (type === "electiveCourses") {
+      // 选修课导出需要 ELECTIVE_READ 权限
+      try {
+        await requirePermission(Permissions.ELECTIVE_READ)
+      } catch (e) {
+        if (e instanceof PermissionDeniedError) {
+          return NextResponse.json(
+            { success: false, message: e.message },
+            { status: 403 }
+          )
+        }
+        throw e
+      }
+      buffer = await exportElectiveCoursesToExcel({
+        status: params.status ? String(params.status) : undefined,
+        teacherId: params.teacherId ? String(params.teacherId) : undefined,
+      })
+      filename = `elective_courses_export_${formatDateForFile()}.xlsx`
+    } else if (type === "courseSelections") {
+      // 选课名单导出需要 ELECTIVE_MANAGE 权限
+      try {
+        await requirePermission(Permissions.ELECTIVE_MANAGE)
+      } catch (e) {
+        if (e instanceof PermissionDeniedError) {
+          return NextResponse.json(
+            { success: false, message: e.message },
+            { status: 403 }
+          )
+        }
+        throw e
+      }
+      buffer = await exportCourseSelectionsToExcel({
+        courseId: String(params.courseId ?? ""),
+      })
+      filename = `course_selections_export_${formatDateForFile()}.xlsx`
     } else if (type === "audit" || type === "login" || type === "dataChange") {
       // Audit-related exports require AUDIT_LOG_READ permission
       try {
@@ -104,7 +177,7 @@ export async function POST(req: Request) {
       }
     } else {
       return NextResponse.json(
-        { success: false, message: "Attendance export not implemented" },
+        { success: false, message: "Export type not implemented" },
         { status: 400 }
       )
     }