✨ 优化邮件验证和密码重置链接

- 修改邮件中的验证和重置链接，直接指向 app.html 页面
- 在落地页添加容错脚本，自动重定向带 token 的请求到应用页
- 提升用户体验，减少跳转步骤

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/server.js

@@ -827,7 +827,7 @@ app.post('/api/register',
         verification_expires_at: expiresAtMs
       });
 
-      const verifyLink = `${getProtocol(req)}://${req.get('host')}/?verifyToken=${verifyToken}`;
+      const verifyLink = `${getProtocol(req)}://${req.get('host')}/app.html?verifyToken=${verifyToken}`;
 
       try {
         await sendMail(
@@ -894,7 +894,7 @@ app.post('/api/resend-verification', [
     const expiresAtMs = Date.now() + 30 * 60 * 1000;
     VerificationDB.setVerification(user.id, verifyToken, expiresAtMs);
 
-    const verifyLink = `${getProtocol(req)}://${req.get('host')}/?verifyToken=${verifyToken}`;
+    const verifyLink = `${getProtocol(req)}://${req.get('host')}/app.html?verifyToken=${verifyToken}`;
     await sendMail(
       user.email,
       '邮箱验证 - 玩玩云',
@@ -959,7 +959,7 @@ app.post('/api/password/forgot', [
     const expiresAtMs = Date.now() + 30 * 60 * 1000;
     PasswordResetTokenDB.create(user.id, token, expiresAtMs);
 
-    const resetLink = `${getProtocol(req)}://${req.get('host')}/?resetToken=${token}`;
+    const resetLink = `${getProtocol(req)}://${req.get('host')}/app.html?resetToken=${token}`;
     await sendMail(
       email,
       '密码重置 - 玩玩云',