feat(mail): Add support for multiple domains per mail service

- Add `Domains` field to MailServiceConfig for managing additional domains under single API
- Implement `matchDomain` helper function for precise and subdomain matching logic
- Update `GetServiceByDomain` to check both primary domain and additional domains list
- Enhance EmailConfig UI to display domain count and allow comma-separated domain input
- Add domains field to mail service request/response structures in API handlers
- Update frontend types to include domains array in MailService interface
- Improve documentation with clarification on primary vs additional domains usage
- Allows single mail service API to manage multiple email domains for verification and operations

backend/cmd/main.go

@@ -140,7 +140,7 @@ func startServer(cfg *config.Config) {
 	mux.HandleFunc("/api/db/owners/clear-used", api.CORS(handleClearUsedOwners))     // 清理已使用
 	mux.HandleFunc("/api/db/owners/delete/", api.CORS(handleDeleteOwner))            // DELETE /api/db/owners/delete/{id}
 	mux.HandleFunc("/api/db/owners/batch-delete", api.CORS(handleBatchDeleteOwners)) // POST 批量删除
-	mux.HandleFunc("/api/db/owners/ids", api.CORS(handleGetOwnerIDs))               // GET 获取所有ID（全选用）
+	mux.HandleFunc("/api/db/owners/ids", api.CORS(handleGetOwnerIDs))                // GET 获取所有ID（全选用）
 	mux.HandleFunc("/api/db/owners/refetch-account-ids", api.CORS(api.HandleRefetchAccountIDs))
 	mux.HandleFunc("/api/upload/validate", api.CORS(api.HandleUploadValidate))
 
@@ -739,6 +739,7 @@ func handleMailServices(w http.ResponseWriter, r *http.Request) {
 				"apiBase":    s.APIBase,
 				"apiToken":   s.APIToken,
 				"domain":     s.Domain,
+				"domains":    s.Domains,
 				"emailPath":  s.EmailPath,
 				"addUserApi": s.AddUserAPI,
 			}
@@ -747,12 +748,13 @@ func handleMailServices(w http.ResponseWriter, r *http.Request) {
 	case "POST":
 		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"`
+				Name       string   `json:"name"`
+				APIBase    string   `json:"apiBase"`
+				APIToken   string   `json:"apiToken"`
+				Domain     string   `json:"domain"`
+				Domains    []string `json:"domains"`
+				EmailPath  string   `json:"emailPath"`
+				AddUserAPI string   `json:"addUserApi"`
 			} `json:"services"`
 		}
 
@@ -778,6 +780,7 @@ func handleMailServices(w http.ResponseWriter, r *http.Request) {
 				APIBase:    s.APIBase,
 				APIToken:   s.APIToken,
 				Domain:     s.Domain,
+				Domains:    s.Domains,
 				EmailPath:  emailPath,
 				AddUserAPI: addUserAPI,
 			})