feat: 添加SMTP邮件通知功能

新增功能：
- 支持SMTP邮件通知平台，可通过邮件接收系统通知
- 支持配置SMTP服务器、端口、用户名、密码、发件人和收件人
- 支持TLS/SSL加密连接
- 提供美观的HTML邮件模板和纯文本备用格式

代码优化：
- 重构邮件格式化逻辑，提取buildNotificationDetails减少重复代码
- 优化前端表单验证逻辑，提取validatePlatformForm统一验证
- 清理UI中的冗余提示信息和配置项

UI改进：
- 移除SMTP配置说明文字
- 移除超时设置和忽略TLS证书验证选项
- 简化测试成功提示消息
- SMTP平台显示收件人邮箱而非URL

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

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

src/services/webhookService.js

@@ -1,5 +1,6 @@
 const axios = require('axios')
 const crypto = require('crypto')
+const nodemailer = require('nodemailer')
 const logger = require('../utils/logger')
 const webhookConfigService = require('./webhookConfigService')
 const { getISOStringWithTimezone } = require('../utils/dateHelper')
@@ -14,7 +15,8 @@ class WebhookService {
       slack: this.sendToSlack.bind(this),
       discord: this.sendToDiscord.bind(this),
       custom: this.sendToCustom.bind(this),
-      bark: this.sendToBark.bind(this)
+      bark: this.sendToBark.bind(this),
+      smtp: this.sendToSMTP.bind(this)
     }
     this.timezone = appConfig.system.timezone || 'Asia/Shanghai'
   }
@@ -243,6 +245,51 @@ class WebhookService {
     await this.sendHttpRequest(url, payload, platform.timeout || 10000)
   }
 
+  /**
+   * SMTP邮件通知
+   */
+  async sendToSMTP(platform, type, data) {
+    try {
+      // 创建SMTP传输器
+      const transporter = nodemailer.createTransport({
+        host: platform.host,
+        port: platform.port || 587,
+        secure: platform.secure || false, // true for 465, false for other ports
+        auth: {
+          user: platform.user,
+          pass: platform.pass
+        },
+        // 可选的TLS配置
+        tls: platform.ignoreTLS ? { rejectUnauthorized: false } : undefined,
+        // 连接超时
+        connectionTimeout: platform.timeout || 10000
+      })
+
+      // 构造邮件内容
+      const subject = this.getNotificationTitle(type)
+      const htmlContent = this.formatMessageForEmail(type, data)
+      const textContent = this.formatMessageForEmailText(type, data)
+
+      // 邮件选项
+      const mailOptions = {
+        from: platform.from || platform.user, // 发送者
+        to: platform.to, // 接收者（必填）
+        subject: `[Claude Relay Service] ${subject}`,
+        text: textContent,
+        html: htmlContent
+      }
+
+      // 发送邮件
+      const info = await transporter.sendMail(mailOptions)
+      logger.info(`✅ 邮件发送成功: ${info.messageId}`)
+
+      return info
+    } catch (error) {
+      logger.error('SMTP邮件发送失败:', error)
+      throw error
+    }
+  }
+
   /**
    * 发送HTTP请求
    */
@@ -459,6 +506,121 @@ class WebhookService {
     return lines.join('\n')
   }
 
+  /**
+   * 构建通知详情数据
+   */
+  buildNotificationDetails(data) {
+    const details = []
+
+    if (data.accountName) {
+      details.push({ label: '账号', value: data.accountName })
+    }
+    if (data.platform) {
+      details.push({ label: '平台', value: data.platform })
+    }
+    if (data.status) {
+      details.push({ label: '状态', value: data.status, color: this.getStatusColor(data.status) })
+    }
+    if (data.errorCode) {
+      details.push({ label: '错误代码', value: data.errorCode, isCode: true })
+    }
+    if (data.reason) {
+      details.push({ label: '原因', value: data.reason })
+    }
+    if (data.message) {
+      details.push({ label: '消息', value: data.message })
+    }
+    if (data.quota) {
+      details.push({ label: '配额', value: `${data.quota.remaining}/${data.quota.total}` })
+    }
+    if (data.usage) {
+      details.push({ label: '使用率', value: `${data.usage}%` })
+    }
+
+    return details
+  }
+
+  /**
+   * 格式化邮件HTML内容
+   */
+  formatMessageForEmail(type, data) {
+    const title = this.getNotificationTitle(type)
+    const timestamp = new Date().toLocaleString('zh-CN', { timeZone: this.timezone })
+    const details = this.buildNotificationDetails(data)
+
+    let content = `
+      <div style="max-width: 600px; margin: 0 auto; font-family: Arial, sans-serif;">
+        <div style="background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); color: white; padding: 20px; border-radius: 8px 8px 0 0;">
+          <h1 style="margin: 0; font-size: 24px;">${title}</h1>
+          <p style="margin: 10px 0 0 0; opacity: 0.9;">Claude Relay Service</p>
+        </div>
+        <div style="background: #f8f9fa; padding: 20px; border: 1px solid #e9ecef; border-top: none; border-radius: 0 0 8px 8px;">
+          <div style="background: white; padding: 16px; border-radius: 6px; box-shadow: 0 2px 4px rgba(0,0,0,0.1);">
+    `
+
+    // 使用统一的详情数据渲染
+    details.forEach((detail) => {
+      if (detail.isCode) {
+        content += `<p><strong>${detail.label}:</strong> <code style="background: #f1f3f4; padding: 2px 6px; border-radius: 4px;">${detail.value}</code></p>`
+      } else if (detail.color) {
+        content += `<p><strong>${detail.label}:</strong> <span style="color: ${detail.color};">${detail.value}</span></p>`
+      } else {
+        content += `<p><strong>${detail.label}:</strong> ${detail.value}</p>`
+      }
+    })
+
+    content += `
+          </div>
+          <div style="margin-top: 20px; padding-top: 16px; border-top: 1px solid #e9ecef; font-size: 14px; color: #6c757d; text-align: center;">
+            <p>发送时间: ${timestamp}</p>
+            <p style="margin: 0;">此邮件由 Claude Relay Service 自动发送</p>
+          </div>
+        </div>
+      </div>
+    `
+
+    return content
+  }
+
+  /**
+   * 格式化邮件纯文本内容
+   */
+  formatMessageForEmailText(type, data) {
+    const title = this.getNotificationTitle(type)
+    const timestamp = new Date().toLocaleString('zh-CN', { timeZone: this.timezone })
+    const details = this.buildNotificationDetails(data)
+
+    let content = `${title}\n`
+    content += `=====================================\n\n`
+
+    // 使用统一的详情数据渲染
+    details.forEach((detail) => {
+      content += `${detail.label}: ${detail.value}\n`
+    })
+
+    content += `\n发送时间: ${timestamp}\n`
+    content += `服务: Claude Relay Service\n`
+    content += `=====================================\n`
+    content += `此邮件由系统自动发送，请勿回复。`
+
+    return content
+  }
+
+  /**
+   * 获取状态颜色
+   */
+  getStatusColor(status) {
+    const colors = {
+      error: '#dc3545',
+      unauthorized: '#fd7e14',
+      blocked: '#6f42c1',
+      disabled: '#6c757d',
+      active: '#28a745',
+      warning: '#ffc107'
+    }
+    return colors[status] || '#007bff'
+  }
+
   /**
    * 格式化通知详情
    */