feat(chinamobile): support doubao-seedance-2-0-mini-260615 billing model

Register the Seedance mini model in the matrix usage capability table
(both native name and doubao-seedance-2.0 alias) and keep
SupportsAnyMatrixUsageBillingModel in sync so the model bills via
matrix usage on the ChinaMobile Seedance channel.

Co-Authored-By: ZCode <noreply@anthropic.com>

relay/helper/matrix_usage_capability.go

@@ -30,6 +30,8 @@ var matrixUsageCapabilities = []MatrixUsageCapability{
 	{BillingModelName: "doubao-seedance-2-0-fast-260128", UpstreamModelName: "doubao-seedance-2-0-fast-260128", ChannelType: constant.ChannelTypeChinaMobileSeedance},
 	{BillingModelName: "doubao-seedance-2-0-fast-260128", UpstreamModelName: "doubao-seedance-2.0", ChannelType: constant.ChannelTypeChinaMobileSeedance},
 	{BillingModelName: "doubao-seedance-2.0", UpstreamModelName: "doubao-seedance-2.0", ChannelType: constant.ChannelTypeChinaMobileSeedance},
+	{BillingModelName: "doubao-seedance-2-0-mini-260615", UpstreamModelName: "doubao-seedance-2-0-mini-260615", ChannelType: constant.ChannelTypeChinaMobileSeedance},
+	{BillingModelName: "doubao-seedance-2-0-mini-260615", UpstreamModelName: "doubao-seedance-2.0", ChannelType: constant.ChannelTypeChinaMobileSeedance},
 	// Keep in sync with SupportsAnyMatrixUsageBillingModel in setting/ratio_setting/model_pricing.go
 	{BillingModelName: "kling-v1", UpstreamModelName: "kling-v1", ChannelType: constant.ChannelTypeKlingAiping},
 	{BillingModelName: "kling-v1", UpstreamModelName: "Kling-V1", ChannelType: constant.ChannelTypeKlingAiping},

setting/ratio_setting/model_pricing.go

@@ -152,7 +152,7 @@ func SupportsAnyMatrixUsageBillingModel(modelName string) bool {
 	// Keep in sync with matrixUsageCapabilities in relay/helper/matrix_usage_capability.go
 	switch modelName {
 	case "seedance-2", "doubao-video", "doubao-video-seedance",
-		"doubao-seedance-2-0-260128", "doubao-seedance-2-0-fast-260128",
+		"doubao-seedance-2-0-260128", "doubao-seedance-2-0-fast-260128", "doubao-seedance-2-0-mini-260615",
 		"Doubao-Seedance-2.0", "Doubao-Seedance-2.0-fast", "Doubao-Seedance-2.0-mini",
 		"kling-v1", "kling-v1-6", "kling-v2-6", "kling-v3",
 		"kling-video-o1", "kling-v3-omni":