feat: 完成 P1 全部功能 + 修复 proxy 导出 + 切换 MySQL 端口至 14013

## P1 功能（20 项）
- 站内消息系统、家长仪表盘、学生考勤管理
- Excel 导入导出、用户批量导入、成绩导出
- 排课规则+自动排课+课表调整
- 成绩趋势+对比分析、密码安全策略、速率限制
- 数据变更日志、文件预览+存储策略、全文检索
- 依赖审计集成 CI、数据库定时备份、E2E 测试完善
- 通知偏好管理

## 基础设施修复
- src/proxy.ts: 将 middleware 导出重命名为 proxy（Next.js 16 要求）
- .env: MySQL 端口从 13002 切换至 14013
- scripts/create-db.ts: 新增数据库初始化脚本

## 架构文档同步
- 004_architecture_impact_map.md 和 005_architecture_data.json
  完整记录所有新增表、模块、路由、权限、依赖关系

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

@@ -0,0 +1,39 @@
+import { getAnnouncements } from "@/modules/announcements/data-access"
+import { getGrades } from "@/modules/school/data-access"
+import { AdminAnnouncementsView } from "@/modules/announcements/components/admin-announcements-view"
+import type { AnnouncementStatus } from "@/modules/announcements/types"
+
+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
+}
+
+const isValidStatus = (v?: string): v is AnnouncementStatus =>
+  v === "draft" || v === "published" || v === "archived"
+
+export default async function AdminAnnouncementsPage({
+  searchParams,
+}: {
+  searchParams: Promise<SearchParams>
+}) {
+  const sp = await searchParams
+  const statusParam = getParam(sp, "status")
+  const status = isValidStatus(statusParam) ? statusParam : undefined
+
+  const [announcements, grades] = await Promise.all([
+    getAnnouncements({ status }),
+    getGrades(),
+  ])
+
+  return (
+    <AdminAnnouncementsView
+      announcements={announcements}
+      grades={grades.map((g) => ({ id: g.id, name: g.name }))}
+      initialStatus={status}
+    />
+  )
+}