feat(auth): 密码重置邮件队列化与限流优化

- 邮件发送改为异步队列处理，避免并发导致发送失败
- 新增 Email 维度限流（30秒冷却期），防止邮件轰炸
- Token 验证使用常量时间比较，防止时序攻击
- 重构代码消除冗余，提取公共验证逻辑

frontend/src/i18n/locales/en.ts

@@ -271,7 +271,36 @@ export default {
       code: 'Code',
       state: 'State',
       fullUrl: 'Full URL'
-    }
+    },
+    // Forgot password
+    forgotPassword: 'Forgot password?',
+    forgotPasswordTitle: 'Reset Your Password',
+    forgotPasswordHint: 'Enter your email address and we will send you a link to reset your password.',
+    sendResetLink: 'Send Reset Link',
+    sendingResetLink: 'Sending...',
+    sendResetLinkFailed: 'Failed to send reset link. Please try again.',
+    resetEmailSent: 'Reset Link Sent',
+    resetEmailSentHint: 'If an account exists with this email, you will receive a password reset link shortly. Please check your inbox and spam folder.',
+    backToLogin: 'Back to Login',
+    rememberedPassword: 'Remembered your password?',
+    // Reset password
+    resetPasswordTitle: 'Set New Password',
+    resetPasswordHint: 'Enter your new password below.',
+    newPassword: 'New Password',
+    newPasswordPlaceholder: 'Enter your new password',
+    confirmPassword: 'Confirm Password',
+    confirmPasswordPlaceholder: 'Confirm your new password',
+    confirmPasswordRequired: 'Please confirm your password',
+    passwordsDoNotMatch: 'Passwords do not match',
+    resetPassword: 'Reset Password',
+    resettingPassword: 'Resetting...',
+    resetPasswordFailed: 'Failed to reset password. Please try again.',
+    passwordResetSuccess: 'Password Reset Successful',
+    passwordResetSuccessHint: 'Your password has been reset. You can now sign in with your new password.',
+    invalidResetLink: 'Invalid Reset Link',
+    invalidResetLinkHint: 'This password reset link is invalid or has expired. Please request a new one.',
+    requestNewResetLink: 'Request New Reset Link',
+    invalidOrExpiredToken: 'The password reset link is invalid or has expired. Please request a new one.'
   },
 
   // Dashboard
@@ -2743,7 +2772,9 @@ export default {
         emailVerification: 'Email Verification',
         emailVerificationHint: 'Require email verification for new registrations',
         promoCode: 'Promo Code',
-        promoCodeHint: 'Allow users to use promo codes during registration'
+        promoCodeHint: 'Allow users to use promo codes during registration',
+        passwordReset: 'Password Reset',
+        passwordResetHint: 'Allow users to reset their password via email'
       },
       turnstile: {
         title: 'Cloudflare Turnstile',

frontend/src/i18n/locales/zh.ts

@@ -268,7 +268,36 @@ export default {
       code: '授权码',
       state: '状态',
       fullUrl: '完整URL'
-    }
+    },
+    // 忘记密码
+    forgotPassword: '忘记密码？',
+    forgotPasswordTitle: '重置密码',
+    forgotPasswordHint: '输入您的邮箱地址，我们将向您发送密码重置链接。',
+    sendResetLink: '发送重置链接',
+    sendingResetLink: '发送中...',
+    sendResetLinkFailed: '发送重置链接失败，请重试。',
+    resetEmailSent: '重置链接已发送',
+    resetEmailSentHint: '如果该邮箱已注册，您将很快收到密码重置链接。请检查您的收件箱和垃圾邮件文件夹。',
+    backToLogin: '返回登录',
+    rememberedPassword: '想起密码了？',
+    // 重置密码
+    resetPasswordTitle: '设置新密码',
+    resetPasswordHint: '请在下方输入您的新密码。',
+    newPassword: '新密码',
+    newPasswordPlaceholder: '输入新密码',
+    confirmPassword: '确认密码',
+    confirmPasswordPlaceholder: '再次输入新密码',
+    confirmPasswordRequired: '请确认您的密码',
+    passwordsDoNotMatch: '两次输入的密码不一致',
+    resetPassword: '重置密码',
+    resettingPassword: '重置中...',
+    resetPasswordFailed: '重置密码失败，请重试。',
+    passwordResetSuccess: '密码重置成功',
+    passwordResetSuccessHint: '您的密码已重置。现在可以使用新密码登录。',
+    invalidResetLink: '无效的重置链接',
+    invalidResetLinkHint: '此密码重置链接无效或已过期。请重新请求一个新链接。',
+    requestNewResetLink: '请求新的重置链接',
+    invalidOrExpiredToken: '密码重置链接无效或已过期。请重新请求一个新链接。'
   },
 
   // Dashboard
@@ -2896,7 +2925,9 @@ export default {
         emailVerification: '邮箱验证',
         emailVerificationHint: '新用户注册时需要验证邮箱',
         promoCode: '优惠码',
-        promoCodeHint: '允许用户在注册时使用优惠码'
+        promoCodeHint: '允许用户在注册时使用优惠码',
+        passwordReset: '忘记密码',
+        passwordResetHint: '允许用户通过邮箱重置密码'
       },
       turnstile: {
         title: 'Cloudflare Turnstile',