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/shared/lib/excel.ts

@@ -0,0 +1,173 @@
+import "server-only"
+
+import ExcelJS from "exceljs"
+
+export type ExcelColumn = {
+  header: string
+  key: string
+  width?: number
+}
+
+export type ExcelSheet = {
+  name: string
+  columns: ExcelColumn[]
+  rows: Record<string, unknown>[]
+}
+
+export type TemplateColumn = ExcelColumn & {
+  note?: string
+}
+
+export type TemplateSheet = {
+  name: string
+  columns: TemplateColumn[]
+  sampleRows?: Record<string, unknown>[]
+}
+
+export type ParsedSheet = {
+  sheetName: string
+  rows: Record<string, unknown>[]
+}
+
+/**
+ * 导出数据到 Excel Buffer
+ */
+export async function exportToExcel(params: {
+  sheets: ExcelSheet[]
+}): Promise<Buffer> {
+  const workbook = new ExcelJS.Workbook()
+
+  for (const sheet of params.sheets) {
+    const worksheet = workbook.addWorksheet(sheet.name, {
+      views: [{ state: "frozen", ySplit: 1 }],
+    })
+
+    worksheet.columns = sheet.columns.map((col) => ({
+      header: col.header,
+      key: col.key,
+      width: col.width ?? 20,
+    }))
+
+    // Header style
+    const headerRow = worksheet.getRow(1)
+    headerRow.font = { bold: true }
+    headerRow.fill = {
+      type: "pattern",
+      pattern: "solid",
+      fgColor: { argb: "FFE0E7FF" },
+    }
+    headerRow.alignment = { vertical: "middle", horizontal: "left" }
+
+    for (const row of sheet.rows) {
+      worksheet.addRow(row)
+    }
+
+    worksheet.autoFilter = {
+      from: { row: 1, column: 1 },
+      to: { row: 1, column: sheet.columns.length },
+    }
+  }
+
+  const arrayBuffer = await workbook.xlsx.writeBuffer()
+  return Buffer.from(arrayBuffer)
+}
+
+/**
+ * 从 Buffer 解析 Excel
+ */
+export async function parseExcel(buffer: Buffer): Promise<ParsedSheet[]> {
+  const workbook = new ExcelJS.Workbook()
+  await workbook.xlsx.load(buffer as unknown as ArrayBuffer)
+
+  const result: ParsedSheet[] = []
+
+  workbook.worksheets.forEach((worksheet) => {
+    if (worksheet.rowCount === 0) {
+      result.push({ sheetName: worksheet.name, rows: [] })
+      return
+    }
+
+    const headerRow = worksheet.getRow(1)
+    const headers: string[] = []
+    const keys: string[] = []
+
+    headerRow.eachCell((cell, colNumber) => {
+      const header = String(cell.value ?? "").trim()
+      headers.push(header)
+      keys.push(header || `column_${colNumber}`)
+    })
+
+    const rows: Record<string, unknown>[] = []
+    for (let rowNum = 2; rowNum <= worksheet.rowCount; rowNum++) {
+      const row = worksheet.getRow(rowNum)
+      const record: Record<string, unknown> = {}
+      let hasValue = false
+
+      keys.forEach((key, idx) => {
+        const cell = row.getCell(idx + 1)
+        const value = cell.value
+        if (value !== null && value !== undefined && value !== "") {
+          record[key] = typeof value === "object" && "text" in value
+            ? String((value as { text: string }).text)
+            : value
+          hasValue = true
+        } else {
+          record[key] = ""
+        }
+      })
+
+      if (hasValue) rows.push(record)
+    }
+
+    result.push({ sheetName: worksheet.name, rows })
+  })
+
+  return result
+}
+
+/**
+ * 生成导入模板 Buffer
+ */
+export async function generateTemplate(params: {
+  sheets: TemplateSheet[]
+}): Promise<Buffer> {
+  const workbook = new ExcelJS.Workbook()
+
+  for (const sheet of params.sheets) {
+    const worksheet = workbook.addWorksheet(sheet.name)
+
+    worksheet.columns = sheet.columns.map((col) => ({
+      header: col.header,
+      key: col.key,
+      width: col.width ?? 22,
+    }))
+
+    const headerRow = worksheet.getRow(1)
+    headerRow.font = { bold: true }
+    headerRow.fill = {
+      type: "pattern",
+      pattern: "solid",
+      fgColor: { argb: "FFE0E7FF" },
+    }
+
+    // Notes row (row 2)
+    const noteRow = worksheet.getRow(2)
+    sheet.columns.forEach((col, idx) => {
+      const cell = noteRow.getCell(idx + 1)
+      cell.value = col.note ?? ""
+      cell.font = { italic: true, color: { argb: "FF6B7280" } }
+    })
+
+    // Sample rows (starting from row 3)
+    const sampleRows = sheet.sampleRows ?? []
+    sampleRows.forEach((row) => worksheet.addRow(row))
+
+    // Empty row for user input
+    if (sampleRows.length === 0) {
+      worksheet.addRow({})
+    }
+  }
+
+  const arrayBuffer = await workbook.xlsx.writeBuffer()
+  return Buffer.from(arrayBuffer)
+}