fix: 支持零价系统渠道模型分发 (#303)

* docs(spec): 模型计费 - 记录零价免费模型设计

* fix(billing): 模型定价 - 支持零价免费模型

* fix(config): 系统模型目录 - 支持零价模型

backend/internal/repository/finance.go

@@ -615,7 +615,7 @@ func (r *Repository) SettleBillingOrder(id string, providerRequestID string) err
 		if order.Status == model.BillingStatusRefunded {
 			return errors.New("billing order already refunded")
 		}
-		if order.BillingMode == "token" {
+		if order.BillingMode == "token" && !zeroPricedTokenOrder(order) {
 			usage, err := billingUsage(tx, id)
 			if err != nil {
 				return err
@@ -717,6 +717,13 @@ func (r *Repository) SettleBillingOrder(id string, providerRequestID string) err
 	})
 }
 
+func zeroPricedTokenOrder(order model.BillingOrder) bool {
+	return order.BillingMode == "token" &&
+		order.InputTokenPriceMicrocredits == 0 &&
+		order.OutputTokenPriceMicrocredits == 0 &&
+		order.CachedTokenPriceMicrocredits == 0
+}
+
 func (r *Repository) RefundBillingOrder(id string, errorText string) error {
 	return r.db.Transaction(func(tx *gorm.DB) error {
 		var order model.BillingOrder

backend/internal/service/channel_models.go

@@ -473,12 +473,6 @@ func validateChannelModelTierPricing(capability string, protocol model.ChannelIn
 	if !input.PriceConfigured {
 		return nil
 	}
-	if billingMode == "token" && input.InputTokenPriceMicrocredits == 0 && input.OutputTokenPriceMicrocredits == 0 && input.CachedTokenPriceMicrocredits == 0 {
-		return BadAuthRequest("Token 计费至少需要配置一项价格")
-	}
-	if billingMode == "token" && capability == "video" && input.OutputTokenPriceMicrocredits == 0 {
-		return BadAuthRequest("火山方舟视频 Token 计费需要配置每百万视频 Token 价格")
-	}
 	const maxTokenPriceMicrocredits = int64(1_000_000) * CreditScale
 	if input.InputTokenPriceMicrocredits > maxTokenPriceMicrocredits || input.OutputTokenPriceMicrocredits > maxTokenPriceMicrocredits || input.CachedTokenPriceMicrocredits > maxTokenPriceMicrocredits {
 		return BadAuthRequest("Token 每百万用量价格不能超过 1,000,000 积分")

backend/internal/service/logical_models.go

@@ -191,11 +191,11 @@ func publicLogicalModel(cached cachedLogicalModel, available bool) PublicLogical
 		Description: item.Description, Capability: item.Capability, SortOrder: item.SortOrder,
 		PricePolicy: item.PricePolicy, PricingMode: pricingMode, DisplayPrice: displayPrice,
 		PriceLabel: priceLabel, BillingMode: item.BillingMode,
-		UnitPriceMicrocredits: item.UnitPriceMicrocredits,
-		InputPriceMicrocredits: item.InputPriceMicrocredits,
+		UnitPriceMicrocredits:   item.UnitPriceMicrocredits,
+		InputPriceMicrocredits:  item.InputPriceMicrocredits,
 		OutputPriceMicrocredits: item.OutputPriceMicrocredits,
 		CachedPriceMicrocredits: item.CachedPriceMicrocredits,
-		PriceTiers: priceTiers, LegacyModelIDs: decodeLegacyModelIDs(item.LegacyModelIDsJSON),
+		PriceTiers:              priceTiers, LegacyModelIDs: decodeLegacyModelIDs(item.LegacyModelIDsJSON),
 		CapabilitySpec: productSpec, CapabilityProfiles: profiles,
 		DefaultOptions: cached.Defaults, Available: available,
 	}
@@ -693,9 +693,6 @@ func (s *Service) logicalModelBundle(actor *model.User, id string, req LogicalMo
 		if !supportsLogicalModelTokenBilling(capability, enabledRouteProtocols) {
 			return nil, nil, nil, false, BadAuthRequest("Token 计费仅支持文本前台模型，或全部启用供应线路均为火山方舟视频协议的视频前台模型")
 		}
-		if capability == "video" && req.OutputPriceMicrocredits <= 0 {
-			return nil, nil, nil, false, BadAuthRequest("火山方舟视频 Token 计费需要配置每百万视频 Token 价格")
-		}
 	}
 	// 停用必须始终可执行，便于管理员立即阻止失效线路继续对外服务；重新启用时再强校验结构能力和计费可用性。
 	if req.Enabled {

backend/internal/service/model_catalog.go

@@ -144,7 +144,7 @@ func (s *Service) sanitizeChannelModel(cm *model.ChannelModel) PublicChannelMode
 	// 转换为公开的价格档
 	publicTiers := make([]PublicChannelModelPriceTier, 0, len(priceTiers))
 	for _, tier := range priceTiers {
-		if !tier.Enabled || !ValidatePriceTierPrice(&tier, cm.Capability, cm.Protocol) {
+		if !tier.Enabled || !tier.PriceConfigured || !ValidatePriceTierPrice(&tier, cm.Capability, cm.Protocol) {
 			continue
 		}
 		publicTiers = append(publicTiers, PublicChannelModelPriceTier{

backend/internal/service/price_validation.go

@@ -7,20 +7,20 @@ import "infinite-canvas/backend/internal/model"
 func ValidateChannelModelPrice(billingMode string, capability string, protocol model.ChannelInterfaceType, unitPrice, inputPrice, outputPrice, cachedPrice int64) bool {
 	switch billingMode {
 	case "fixed_request":
-		// 固定价格模式：必须配置单价且大于 0
-		return unitPrice > 0
+		// 固定价格模式：0 表示免费，负数无效。
+		return unitPrice >= 0
 	case "per_second":
-		// 按秒计费：必须配置单价且大于 0
-		return unitPrice > 0
+		// 按秒计费：0 表示免费，负数无效。
+		return unitPrice >= 0
 	case "token":
 		if capability == "video" {
-			return protocol == model.ChannelInterfaceVolcengineArkVideo && outputPrice > 0
+			return protocol == model.ChannelInterfaceVolcengineArkVideo && inputPrice >= 0 && outputPrice >= 0 && cachedPrice >= 0
 		}
 		if capability != "" && capability != "text" {
 			return false
 		}
-		// 文本模型：至少配置一项价格
-		return inputPrice > 0 || outputPrice > 0 || cachedPrice > 0
+		// 文本模型：所有 Token 价格为 0 时表示免费。
+		return inputPrice >= 0 && outputPrice >= 0 && cachedPrice >= 0
 	default:
 		return false
 	}
@@ -58,7 +58,7 @@ func HasValidPrice(channelModel *model.ChannelModel) bool {
 	// 如果有价格档，检查价格档
 	if len(channelModel.PriceTiers) > 0 {
 		for _, tier := range channelModel.PriceTiers {
-			if tier.Enabled && ValidatePriceTierPrice(&tier, channelModel.Capability, channelModel.Protocol) {
+			if tier.Enabled && tier.PriceConfigured && ValidatePriceTierPrice(&tier, channelModel.Capability, channelModel.Protocol) {
 				return true
 			}
 		}
@@ -66,7 +66,7 @@ func HasValidPrice(channelModel *model.ChannelModel) bool {
 	}
 
 	// 否则检查模型级别的价格
-	return ValidateChannelModelPrice(channelModel.BillingMode, channelModel.Capability, channelModel.Protocol, channelModel.UnitPriceMicrocredits, channelModel.InputTokenPriceMicrocredits, channelModel.OutputTokenPriceMicrocredits, channelModel.CachedTokenPriceMicrocredits)
+	return channelModel.PriceConfigured && ValidateChannelModelPrice(channelModel.BillingMode, channelModel.Capability, channelModel.Protocol, channelModel.UnitPriceMicrocredits, channelModel.InputTokenPriceMicrocredits, channelModel.OutputTokenPriceMicrocredits, channelModel.CachedTokenPriceMicrocredits)
 }
 
 // ValidateLogicalModelPrice 校验前台模型的价格配置