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)/messages/group-compose/error.tsx

@@ -0,0 +1,24 @@
+"use client"
+
+import { AlertCircle } from "lucide-react"
+import { useTranslations } from "next-intl"
+
+import { EmptyState } from "@/shared/components/ui/empty-state"
+
+export default function GroupComposeMessageError({ reset }: { error: Error & { digest?: string }; reset: () => void }) {
+  const t = useTranslations("messages")
+  return (
+    <div className="flex h-full flex-col items-center justify-center space-y-4 p-8">
+      <EmptyState
+        icon={AlertCircle}
+        title={t("error.loadFailed")}
+        description={t("error.loadFailedDesc")}
+        action={{
+          label: t("error.retry"),
+          onClick: () => reset(),
+        }}
+        className="border-none shadow-none h-auto"
+      />
+    </div>
+  )
+}

src/app/(dashboard)/messages/group-compose/loading.tsx

@@ -0,0 +1,40 @@
+import { Card, CardContent, CardHeader } from "@/shared/components/ui/card"
+import { Skeleton } from "@/shared/components/ui/skeleton"
+
+export default function GroupComposeLoading() {
+  return (
+    <div className="flex h-full flex-col p-8">
+      <div className="mx-auto w-full max-w-3xl space-y-6">
+        <div className="space-y-2">
+          <Skeleton className="h-8 w-48" />
+          <Skeleton className="h-4 w-64" />
+        </div>
+
+        <Card>
+          <CardHeader>
+            <Skeleton className="h-5 w-32" />
+          </CardHeader>
+          <CardContent className="space-y-4">
+            <div className="space-y-2">
+              <Skeleton className="h-4 w-16" />
+              <Skeleton className="h-10 w-full" />
+            </div>
+            <div className="space-y-2">
+              <Skeleton className="h-4 w-20" />
+              <Skeleton className="h-10 w-full" />
+            </div>
+            <div className="space-y-2">
+              <Skeleton className="h-4 w-16" />
+              <Skeleton className="h-32 w-full" />
+            </div>
+          </CardContent>
+        </Card>
+
+        <div className="flex justify-end gap-3">
+          <Skeleton className="h-10 w-24" />
+          <Skeleton className="h-10 w-28" />
+        </div>
+      </div>
+    </div>
+  )
+}

src/app/(dashboard)/messages/group-compose/page.tsx

@@ -0,0 +1,52 @@
+import type { Metadata } from "next"
+import type { JSX } from "react"
+import { notFound } from "next/navigation"
+import { getTranslations } from "next-intl/server"
+
+import { requirePermission } from "@/shared/lib/auth-guard"
+import { Permissions } from "@/shared/types/permissions"
+import { SectionErrorBoundary } from "@/shared/components/section-error-boundary"
+import { getClassNamesByIds } from "@/modules/classes/data-access"
+
+import { MessageGroupCompose } from "@/modules/messaging/components/message-group-compose"
+
+export const dynamic = "force-dynamic"
+
+export async function generateMetadata(): Promise<Metadata> {
+  const t = await getTranslations("messages")
+  return {
+    title: t("title.groupCompose"),
+    description: t("description.groupCompose"),
+  }
+}
+
+export default async function GroupComposeMessagePage(): Promise<JSX.Element> {
+  const ctx = await requirePermission(Permissions.MESSAGE_SEND)
+  const t = await getTranslations("messages")
+
+  // P2-2: 群发仅限教师（class_taught DataScope）；其他角色无权访问此页面
+  if (ctx.dataScope.type !== "class_taught") {
+    notFound()
+  }
+
+  const classIds = ctx.dataScope.classIds
+  const classNameMap = await getClassNamesByIds(classIds)
+  const classOptions = classIds.map((id) => ({
+    id,
+    name: classNameMap.get(id) ?? id,
+  }))
+
+  return (
+    <div className="flex h-full flex-col p-8">
+      <div className="mx-auto w-full max-w-3xl space-y-6">
+        <div>
+          <h2 className="text-2xl font-bold tracking-tight">{t("title.groupCompose")}</h2>
+          <p className="text-muted-foreground">{t("description.groupCompose")}</p>
+        </div>
+        <SectionErrorBoundary namespace="messages">
+          <MessageGroupCompose classOptions={classOptions} />
+        </SectionErrorBoundary>
+      </div>
+    </div>
+  )
+}