实现Claude渠道请求穿透功能

- 修改 relay/channel/claude/adaptor.go 支持请求头穿透
- 穿透模式下保持原始请求头完整性，仅替换必要的API密钥
- 非穿透模式保持原有逻辑不变
- 新增 docker-compose-custom.yml 用于自定义版本部署

🤖 Generated with [Claude Code](https://claude.ai/code)

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

relay/channel/claude/adaptor.go

@@ -55,14 +55,34 @@ func (a *Adaptor) GetRequestURL(info *relaycommon.RelayInfo) (string, error) {
 }
 
 func (a *Adaptor) SetupRequestHeader(c *gin.Context, req *http.Header, info *relaycommon.RelayInfo) error {
-	channel.SetupApiRequestHeader(info, c, req)
-	req.Set("x-api-key", info.ApiKey)
-	anthropicVersion := c.Request.Header.Get("anthropic-version")
-	if anthropicVersion == "" {
-		anthropicVersion = "2023-06-01"
+	if model_setting.GetGlobalSettings().PassThroughRequestEnabled {
+		// 穿透模式：直接复制原始请求头，但跳过系统级头信息
+		for key, values := range c.Request.Header {
+			keyLower := strings.ToLower(key)
+			if keyLower == "host" || keyLower == "content-length" || keyLower == "connection" {
+				continue
+			}
+			for _, value := range values {
+				req.Add(key, value)
+			}
+		}
+	} else {
+		// 非穿透模式：使用通用设置
+		channel.SetupApiRequestHeader(info, c, req)
+	}
+	
+	// 无论哪种模式都需要设置正确的API密钥
+	req.Set("x-api-key", info.ApiKey)
+	
+	if !model_setting.GetGlobalSettings().PassThroughRequestEnabled {
+		// 非穿透模式才强制设置这些头
+		anthropicVersion := c.Request.Header.Get("anthropic-version")
+		if anthropicVersion == "" {
+			anthropicVersion = "2023-06-01"
+		}
+		req.Set("anthropic-version", anthropicVersion)
+		model_setting.GetClaudeSettings().WriteHeaders(info.OriginModelName, req)
 	}
-	req.Set("anthropic-version", anthropicVersion)
-	model_setting.GetClaudeSettings().WriteHeaders(info.OriginModelName, req)
 	return nil
 }