feat: configurable tool pricing, Sub2API channel, and alpha search billing

Add admin-configurable tool-call prices with cross-provider surcharge
settlement, Sub2API channel support, /v1/alpha/search relay, and usage-log
surcharge UI.

common/api_type.go

@@ -77,6 +77,8 @@ func ChannelType2APIType(channelType int) (int, bool) {
 		apiType = constant.APITypeCodex
 	case constant.ChannelTypeAdvancedCustom:
 		apiType = constant.APITypeAdvancedCustom
+	case constant.ChannelTypeSub2API:
+		apiType = constant.APITypeSub2API
 	}
 	if apiType == -1 {
 		return constant.APITypeOpenAI, false

common/endpoint_defaults.go

@@ -20,6 +20,7 @@ var defaultEndpointInfoMap = map[constant.EndpointType]EndpointInfo{
 	constant.EndpointTypeOpenAI:                {Path: "/v1/chat/completions", Method: "POST"},
 	constant.EndpointTypeOpenAIResponse:        {Path: "/v1/responses", Method: "POST"},
 	constant.EndpointTypeOpenAIResponseCompact: {Path: "/v1/responses/compact", Method: "POST"},
+	constant.EndpointTypeOpenAIAlphaSearch:     {Path: "/v1/alpha/search", Method: "POST"},
 	constant.EndpointTypeAnthropic:             {Path: "/v1/messages", Method: "POST"},
 	constant.EndpointTypeGemini:                {Path: "/v1beta/models/{model}:generateContent", Method: "POST"},
 	constant.EndpointTypeJinaRerank:            {Path: "/v1/rerank", Method: "POST"},

common/endpoint_type.go

@@ -30,6 +30,20 @@ func GetEndpointTypesByChannelType(channelType int, modelName string) []constant
 		endpointTypes = []constant.EndpointType{constant.EndpointTypeOpenAI, constant.EndpointTypeOpenAIResponse}
 	case constant.ChannelTypeSora:
 		endpointTypes = []constant.EndpointType{constant.EndpointTypeOpenAIVideo}
+	case constant.ChannelTypeSub2API:
+		endpointTypes = []constant.EndpointType{
+			constant.EndpointTypeOpenAI,
+			constant.EndpointTypeOpenAIResponse,
+			constant.EndpointTypeAnthropic,
+			constant.EndpointTypeGemini,
+			constant.EndpointTypeOpenAIAlphaSearch,
+		}
+	case constant.ChannelTypeCodex:
+		endpointTypes = []constant.EndpointType{
+			constant.EndpointTypeOpenAIResponse,
+			constant.EndpointTypeOpenAIResponseCompact,
+			constant.EndpointTypeOpenAIAlphaSearch,
+		}
 	default:
 		if IsOpenAIResponseOnlyModel(modelName) {
 			endpointTypes = []constant.EndpointType{constant.EndpointTypeOpenAIResponse}