feat(app): add error/loading boundaries across all dashboard routes and new routes

- Add error.tsx and loading.tsx boundaries for admin, parent, student, teacher routes

- Add admin announcements edit, audit-logs overview, curriculum-map, invitation-codes, permissions, questions, roles routes

- Add admin elective detail and components, files, course-plans, users, scheduling boundaries

- Add messages group-compose route

- Add parent course-plans, elective, grades report-card, practice routes

- Add student course-plans, elective detail, error-book dialogs, grades report-card, learning study-path, leave, schedule boundaries

- Add teacher attendance report, classes boundaries, course-plans boundaries, elective, exams analytics/edit-rich/all/create/new, grades report-card, homework boundaries, leave, lesson-plans calendar

- Add auth loading, onboarding loading, api cron

src/app/(dashboard)/student/learning/textbooks/[id]/page.tsx

@@ -1,3 +1,4 @@
+import type { JSX } from "react"
 import { notFound } from "next/navigation"
 import { getTranslations } from "next-intl/server"
 
@@ -10,6 +11,8 @@ import { Badge } from "@/shared/components/ui/badge"
 import { EmptyState } from "@/shared/components/ui/empty-state"
 import { getCurrentStudentUser } from "@/modules/users/data-access"
 import { getGradeNameById } from "@/modules/school/data-access"
+import { requirePermission } from "@/shared/lib/auth-guard"
+import { Permissions } from "@/shared/types/permissions"
 
 export const dynamic = "force-dynamic"
 
@@ -17,8 +20,10 @@ export default async function StudentTextbookDetailPage({
   params,
 }: {
   params: Promise<{ id: string }>
-}) {
+}): Promise<JSX.Element> {
   const t = await getTranslations("textbooks")
+  // P0 显式权限校验：与教师端一致，校验 TEXTBOOK_READ 权限点
+  await requirePermission(Permissions.TEXTBOOK_READ)
   const student = await getCurrentStudentUser()
   if (!student) return notFound()