退款审核功能：待交接取消不再自动退款，改为客服审核后原路退回

- 租客在待交接状态取消订单不再自动退款，改为 refund_status=pending_review
- 新增退款审核页面 /admin/orders/refund-review，客服可逐个审核
- 新增 POST /refund/approve 通过退款、POST /refund/reject 驳回退款
- 新增 GET /orders/refund-pending 查询待审核退款订单列表
- 优化状态标签表述：已取消→租客已取消、已关闭→客服已关闭、异常→客服介入
- 新增 refund_status: pending_review 及其前端标签「待客服审核退款」
- AdminOrderDetailView 退款状态改用统一 refundStatusLabel

backend/internal/modules/order/handler_admin.go

@@ -96,6 +96,39 @@ func (h *Handler) AdminRefundStatus(c *gin.Context) {
 	response.OK(c, item)
 }
 
+func (h *Handler) AdminApproveRefund(c *gin.Context) {
+	orderID, ok := parseID(c)
+	if !ok {
+		return
+	}
+	if err := h.service.AdminApproveRefund(c.Request.Context(), orderID); err != nil {
+		writeOrderError(c, err)
+		return
+	}
+	response.OK(c, gin.H{"approved": true})
+}
+
+func (h *Handler) AdminRejectRefund(c *gin.Context) {
+	orderID, ok := parseID(c)
+	if !ok {
+		return
+	}
+	if err := h.service.AdminRejectRefund(c.Request.Context(), orderID); err != nil {
+		writeOrderError(c, err)
+		return
+	}
+	response.OK(c, gin.H{"rejected": true})
+}
+
+func (h *Handler) ListPendingRefund(c *gin.Context) {
+	items, err := h.service.ListPendingRefund(c.Request.Context())
+	if err != nil {
+		writeOrderError(c, err)
+		return
+	}
+	response.OK(c, gin.H{"items": items})
+}
+
 func (h *Handler) adminAction(c *gin.Context, fn func(context.Context, uint64, uint64, AdminActionRequest, AuditMeta) error, okData gin.H) {
 	adminID, ok := currentAdminID(c)
 	if !ok {