fix: 根本修复 getClientIP tree-shaking 问题

- audit.ts: 直接定义 getClientIP 函数，而非从 shared 库 re-export
- 原因: Next.js standalone 构建的 tree-shaking 会丢弃 re-export 的函数
- 影响: 修复所有使用 getClientIP 的 API 路由（scan-emails、scan-status、auth/login）

src/app/api/monitor/scan-emails/route.ts

@@ -8,16 +8,9 @@ import { getMonitorConfig } from '@/lib/monitor/settings-manager'
 import { ImapFlow } from 'imapflow'
 import { simpleParser } from 'mailparser'
 import { formatBeijingTime } from '@/lib/monitor/types'
-import { writeAuditLog } from '@/lib/audit'
+import { writeAuditLog, getClientIP } from '@/lib/audit'
 import { getScanState, setScanState, isCancelRequested, resetCancelFlag } from '@/lib/monitor/scan-state'
 
-// 直接定义，避免 Next.js tree-shaking 导致模块导出缺失
-function getClientIP(request: NextRequest): string | null {
-  const forwarded = request.headers.get('x-forwarded-for')
-  if (forwarded) return forwarded.split(',')[0].trim()
-  return request.headers.get('x-real-ip') ?? null
-}
-
 interface ScanResult {
   status: 'running' | 'completed' | 'error' | 'cancelling'
   startedAt: string

src/app/api/monitor/scan-status/route.ts

@@ -3,16 +3,9 @@ import { NextRequest, NextResponse } from 'next/server'
 import { initDatabase } from '@/lib/db-schema'
 import { getCurrentUser } from '@/lib/auth'
 import { hasPermission } from '@/lib/permissions'
-import { writeAuditLog } from '@/lib/audit'
+import { getClientIP, writeAuditLog } from '@/lib/audit'
 import { getScanState, requestCancel } from '@/lib/monitor/scan-state'
 
-// 直接定义，避免 Next.js tree-shaking 导致模块导出缺失
-function getClientIP(request: NextRequest): string | null {
-  const forwarded = request.headers.get('x-forwarded-for')
-  if (forwarded) return forwarded.split(',')[0].trim()
-  return request.headers.get('x-real-ip') ?? null
-}
-
 export async function GET(request: NextRequest) {
   initDatabase()
   const user = await getCurrentUser()

src/lib/audit.ts

@@ -1,6 +1,6 @@
 // issue-ai/src/lib/audit.ts — 站点审计包装器（引用共享库）
 import { getDb } from './db'
-import { writeAuditLog as sharedWriteAuditLog, diffObjects, getClientIP } from '@shared/lib/audit/write-audit-log'
+import { writeAuditLog as sharedWriteAuditLog, diffObjects } from '@shared/lib/audit/write-audit-log'
 import type { AuditLogEntry, AuditStore } from '@shared/lib/audit/write-audit-log'
 
 // 创建 issue-ai 的 store 适配器
@@ -19,5 +19,13 @@ export function writeAuditLog(opts: AuditLogEntry): void {
   sharedWriteAuditLog(store, opts)
 }
 
+// 直接定义 getClientIP，避免 Next.js tree-shaking 导致 re-export 丢失
+// （shared 库的 re-export 在 standalone 构建中可能被优化掉）
+export function getClientIP(request: Request): string | null {
+  const forwarded = request.headers.get('x-forwarded-for')
+  if (forwarded) return forwarded.split(',')[0].trim()
+  return request.headers.get('x-real-ip') ?? null
+}
+
 // re-export 共享工具函数
-export { diffObjects, getClientIP }
+export { diffObjects }