fix(distribution): 修正分销模式判定与结算入账，冻结未确认分成

按买卖站点纯函数判定五种模式，分站卖主站货命中 two_party_platform_receive。
结算批次只收本站 site party，平台分成不再进入分销钱包；生产环境冻结结算入账与站点提现。

backend/internal/modules/distribution/handler.go

@@ -698,7 +698,6 @@ func (h *Handler) GetDashboardAnalytics(c *gin.Context) {
 	response.OK(c, analytics)
 }
 
-
 func isHTTPSRequest(c *gin.Context) bool {
 	if c.Request.TLS != nil {
 		return true
@@ -742,6 +741,8 @@ func writeError(c *gin.Context, err error) {
 		response.Error(c, http.StatusForbidden, "admin_disabled", "分销管理员账号已被禁用")
 	case errors.Is(err, ErrInvalidAmount), errors.Is(err, ErrInvalidRate), errors.Is(err, ErrInvalidServiceUnit), errors.Is(err, ErrUnsupportedMode), errors.Is(err, ErrInvalidOrderKind), errors.Is(err, ErrInvalidPeriod), errors.Is(err, ErrBatchAlreadySettled), errors.Is(err, ErrSettlementBatchEmpty), errors.Is(err, ErrSettlementTotalMismatch):
 		response.BadRequest(c, "分销规则参数不正确")
+	case errors.Is(err, ErrLiveMoneyMovementFrozen):
+		response.Error(c, http.StatusForbidden, "settlement_frozen", "分销结算与提现已冻结，待分成口径确认后再开放")
 	case errors.Is(err, ErrSiteAccessDenied):
 		response.Error(c, http.StatusForbidden, "forbidden", "无权访问该分销站点")
 	case errors.Is(err, ErrDependencyUnavailable):