fix: 按实际纯币结算金额计算保险费用

backend/internal/modules/order/pricing.go

@@ -406,7 +406,7 @@ func calculateCheckoutSettlement(order model.RentalOrder, consumableAmountCent i
 	// 可完结时租客实际承担的租金向金额；有 shortfall 时仍展示完整应付便于协商
 	actualRentAmountCent := actualBuyerRentCent
 	ownerRentIncomeCent := actualOwnerRentCent
-	insuranceFeeCent := calculateInsuranceFeeCent(ownerRentIncomeCent, order.InsuranceFeeBps)
+	insuranceFeeCent := calculateInsuranceFeeCent(usedOwnerCoinPriceCent, order.InsuranceFeeBps)
 	ownerRentIncomeCent = maxCent(ownerRentIncomeCent-insuranceFeeCent, 0)
 	platformFeeCent := maxCent(actualRentAmountCent-ownerRentIncomeCent, 0)
 	depositCompensationCent := damageAppliedCent

backend/internal/modules/order/pricing_insurance_test.go

@@ -49,13 +49,48 @@ func TestCalculateCheckoutSettlementDeductsPremiumInsuranceFee(t *testing.T) {
 	}
 
 	settlement := calculateCheckoutSettlement(order, 12000, 100, 0)
-	if settlement.InsuranceFeeBps != 400 || settlement.InsuranceFeeCent != 1412 {
+	if settlement.InsuranceFeeBps != 400 || settlement.InsuranceFeeCent != 932 {
 		t.Fatalf("保险费用快照不正确: bps=%d fee=%d", settlement.InsuranceFeeBps, settlement.InsuranceFeeCent)
 	}
-	if settlement.OwnerRentIncomeCent != 33888 {
-		t.Fatalf("号主净租金 = %d, want 33888", settlement.OwnerRentIncomeCent)
+	if settlement.OwnerRentIncomeCent != 34368 {
+		t.Fatalf("号主净租金 = %d, want 34368", settlement.OwnerRentIncomeCent)
 	}
-	if settlement.PlatformFeeCent != 4412 {
-		t.Fatalf("平台收入 = %d, want 4412", settlement.PlatformFeeCent)
+	if settlement.PlatformFeeCent != 3932 {
+		t.Fatalf("平台收入 = %d, want 3932", settlement.PlatformFeeCent)
+	}
+}
+
+func TestCalculateCheckoutSettlementUsesActualPureCoinAsInsuranceBase(t *testing.T) {
+	order := model.RentalOrder{
+		RentAmountCent:      25000,
+		OwnerRentAmountCent: 25000,
+		DepositAmountCent:   15000,
+		InsuranceFeeBps:     800,
+		AccountSnapshot: datatypes.JSON([]byte(`{
+			"haf_coin_amount": 100000000,
+			"asset_summary": {
+				"price_breakdown": {
+					"buyer_ratio": 40,
+					"seller_ratio": 40,
+					"buyer_coin_base_price": 250,
+					"seller_coin_base_price": 250,
+					"consumable_price": 0
+				}
+			}
+		}`)),
+	}
+
+	settlement := calculateCheckoutSettlement(order, 5000, 50, 0)
+	if settlement.PureCoinAmountCent != 12500 {
+		t.Fatalf("实际纯币原价 = %d, want 12500", settlement.PureCoinAmountCent)
+	}
+	if settlement.InsuranceFeeCent != 1000 {
+		t.Fatalf("保险费用 = %d, want 1000", settlement.InsuranceFeeCent)
+	}
+	if settlement.ExtraItemAmountCent != 5000 {
+		t.Fatalf("额外物品 = %d, want 5000", settlement.ExtraItemAmountCent)
+	}
+	if settlement.OwnerRentIncomeCent != 16500 {
+		t.Fatalf("号主净租金 = %d, want 16500", settlement.OwnerRentIncomeCent)
 	}
 }