feat: establish core backend API server with S2A proxy, configuration, and mail services, alongside frontend email configuration page and toast component.

backend/cmd/main.go

@@ -355,7 +355,61 @@ func handleMailServices(w http.ResponseWriter, r *http.Request) {
 		}
 		api.Success(w, safeServices)
 	case "POST":
-		api.Error(w, http.StatusNotImplemented, "更新邮箱服务配置暂未实现")
+		var req struct {
+			Services []struct {
+				Name       string `json:"name"`
+				APIBase    string `json:"apiBase"`
+				APIToken   string `json:"apiToken"`
+				Domain     string `json:"domain"`
+				EmailPath  string `json:"emailPath"`
+				AddUserAPI string `json:"addUserApi"`
+			} `json:"services"`
+		}
+
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			logger.Error(fmt.Sprintf("解析邮箱服务配置失败: %v", err), "", "mail")
+			api.Error(w, http.StatusBadRequest, "解析请求失败")
+			return
+		}
+
+		// 转换为 config.MailServiceConfig
+		var services []config.MailServiceConfig
+		for _, s := range req.Services {
+			emailPath := s.EmailPath
+			if emailPath == "" {
+				emailPath = "/api/public/emailList"
+			}
+			addUserAPI := s.AddUserAPI
+			if addUserAPI == "" {
+				addUserAPI = "/api/public/addUser"
+			}
+			services = append(services, config.MailServiceConfig{
+				Name:       s.Name,
+				APIBase:    s.APIBase,
+				APIToken:   s.APIToken,
+				Domain:     s.Domain,
+				EmailPath:  emailPath,
+				AddUserAPI: addUserAPI,
+			})
+		}
+
+		// 更新邮箱服务配置
+		mail.Init(services)
+
+		// 保存到全局配置
+		if config.Global != nil {
+			config.Global.MailServices = services
+		}
+
+		logger.Success(fmt.Sprintf("邮箱服务配置已保存: %d 个服务", len(services)), "", "mail")
+		for _, s := range services {
+			logger.Info(fmt.Sprintf("  - %s (%s) @ %s", s.Name, s.Domain, s.APIBase), "", "mail")
+		}
+
+		api.Success(w, map[string]interface{}{
+			"message": fmt.Sprintf("已保存 %d 个邮箱服务配置", len(services)),
+			"count":   len(services),
+		})
 	default:
 		api.Error(w, http.StatusMethodNotAllowed, "不支持的方法")
 	}

frontend/src/components/common/Toast.tsx

@@ -78,7 +78,7 @@ function ToastContainer({ toasts, onRemove }: ToastContainerProps) {
     if (toasts.length === 0) return null
 
     return (
-        <div className="fixed bottom-6 right-6 z-[9999] space-y-3">
+        <div className="fixed top-6 right-6 z-[9999] space-y-3">
             {toasts.map((toast) => (
                 <ToastItem key={toast.id} toast={toast} onRemove={onRemove} />
             ))}

frontend/src/pages/EmailConfig.tsx

@@ -1,13 +1,15 @@
 import { useState, useEffect } from 'react'
 import { CheckCircle, Save, Mail, Plus, Trash2, TestTube, Loader2, Settings, Server } from 'lucide-react'
-import { Card, CardHeader, CardTitle, CardContent, Button, Input } from '../components/common'
+import { Card, CardHeader, CardTitle, CardContent, Button, Input, useToast } from '../components/common'
 import { useConfig } from '../hooks/useConfig'
 import type { MailServiceConfig } from '../types'
 
 export default function EmailConfig() {
     const { config, updateEmailConfig } = useConfig()
+    const toast = useToast()
 
     const [saved, setSaved] = useState(false)
+    const [saving, setSaving] = useState(false)
     const [services, setServices] = useState<MailServiceConfig[]>(config.email?.services || [])
     const [testingIndex, setTestingIndex] = useState<number | null>(null)
     const [testResults, setTestResults] = useState<Record<number, { success: boolean; message: string }>>({})
@@ -20,6 +22,12 @@ export default function EmailConfig() {
     }, [config.email?.services])
 
     const handleSave = async () => {
+        if (services.length === 0) {
+            toast.warning('请至少添加一个邮箱服务')
+            return
+        }
+
+        setSaving(true)
         // 保存到前端 context
         updateEmailConfig({ services })
 
@@ -31,13 +39,20 @@ export default function EmailConfig() {
                 body: JSON.stringify({ services }),
             })
 
-            if (res.ok) {
+            const data = await res.json()
+
+            if (res.ok && data.code === 0) {
                 setSaved(true)
                 setTimeout(() => setSaved(false), 2000)
+                toast.success(`保存成功: ${data.data.message}`)
+            } else {
+                toast.error('保存失败: ' + (data.message || '未知错误'))
             }
         } catch (error) {
             console.error('保存失败:', error)
+            toast.error('保存失败: ' + (error instanceof Error ? error.message : '网络错误'))
         }
+        setSaving(false)
     }
 
     const handleAddService = () => {
@@ -121,9 +136,11 @@ export default function EmailConfig() {
                     </Button>
                     <Button
                         onClick={handleSave}
+                        disabled={saving}
+                        loading={saving}
                         icon={saved ? <CheckCircle className="h-4 w-4" /> : <Save className="h-4 w-4" />}
                     >
-                        {saved ? '已保存' : '保存配置'}
+                        {saved ? '已保存' : saving ? '保存中...' : '保存配置'}
                     </Button>
                 </div>
             </div>