feat: Initialize backend API server with S2A proxy, mail service management, team processing, and add frontend email configuration page.

backend/internal/api/team_process.go

@@ -258,6 +258,7 @@ func processSingleTeam(idx int, req TeamProcessRequest) TeamProcessResult {
 	if owner.AccountID != "" {
 		// 直接使用数据库中存储的 account_id
 		teamID = owner.AccountID
+		inviter.SetAccountID(teamID) // 必须设置到 inviter 中
 		logger.Info(fmt.Sprintf("%s 使用已存储的 Team ID: %s", logPrefix, teamID), owner.Email, "team")
 	} else {
 		// 如果没有存储，才请求 API 获取