fix: 邮件懒加载、cloudEnabled 刷新、邮箱写入时机、验证码重发冷却

- server/lib/email.ts: transporter 改为懒加载，避免 ESM import 提升导致 EMAIL_PASS 未加载
- server/routes/auth.ts: send-verify 改为写 pendingEmail，验证成功后才写 email；新增 60s 冷却；catch 块打印错误
- server/db.ts: 新增 pendingEmail 字段及迁移
- src/stores/appStore.ts: 新增 refreshCurrentUser，启动时调用 apiGetMe 拉取真实 cloudEnabled
- src/App.tsx: 启动时调用 refreshCurrentUser
- ProfileModal/AccountModal: 加入 60s 倒计时和重新发送按钮

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/lib/email.ts

@@ -1,17 +1,19 @@
 import nodemailer from 'nodemailer'
 
-const transporter = nodemailer.createTransport({
-  host: 'smtp.126.com',
-  port: 465,
-  secure: true,
-  auth: {
-    user: 'mikivl@126.com',
-    pass: process.env.EMAIL_PASS!,
-  },
-})
+function createTransporter() {
+  return nodemailer.createTransport({
+    host: 'smtp.126.com',
+    port: 465,
+    secure: true,
+    auth: {
+      user: 'mikivl@126.com',
+      pass: process.env.EMAIL_PASS!,
+    },
+  })
+}
 
 export async function sendVerifyCode(to: string, code: string) {
-  await transporter.sendMail({
+  await createTransporter().sendMail({
     from: '"MikiVL 笔记" <mikivl@126.com>',
     to,
     subject: '邮箱验证码',
@@ -21,7 +23,7 @@ export async function sendVerifyCode(to: string, code: string) {
 }
 
 export async function sendResetCode(to: string, code: string) {
-  await transporter.sendMail({
+  await createTransporter().sendMail({
     from: '"MikiVL 笔记" <mikivl@126.com>',
     to,
     subject: '重置密码验证码',