feat(ai-proxy): add Claude Code mode support for Claude provider

Add claudeCodeMode configuration option to emulate Claude Code client
requests, enabling OAuth token authentication with Claude API.

Changes:
- Add claudeCodeMode config field in ProviderConfig
- Transform request headers for Claude Code mode:
  - Use Bearer token authorization instead of x-api-key
  - Set user-agent to claude-cli/2.1.2 (external, cli)
  - Set x-app: cli header
  - Set anthropic-beta with OAuth and Claude Code features
  - Add ?beta=true query parameter to path
- Add cache_control with ephemeral type to system prompts in Claude Code mode

This allows users to use Claude Code OAuth tokens with Higress AI proxy.

plugins/wasm-go/extensions/ai-proxy/provider/claude.go

@@ -19,6 +19,10 @@ const (
 	claudeDomain           = "api.anthropic.com"
 	claudeDefaultVersion   = "2023-06-01"
 	claudeDefaultMaxTokens = 4096
+
+	// Claude Code mode constants
+	claudeCodeUserAgent    = "claude-cli/2.1.2 (external, cli)"
+	claudeCodeBetaFeatures = "oauth-2025-04-20,interleaved-thinking-2025-05-14,claude-code-20250219"
 )
 
 type claudeProviderInitializer struct{}
@@ -319,13 +323,36 @@ func (c *claudeProvider) TransformRequestHeaders(ctx wrapper.HttpContext, apiNam
 	util.OverwriteRequestPathHeaderByCapability(headers, string(apiName), c.config.capabilities)
 	util.OverwriteRequestHostHeader(headers, claudeDomain)
 
-	headers.Set("x-api-key", c.config.GetApiTokenInUse(ctx))
-
 	if c.config.apiVersion == "" {
 		c.config.apiVersion = claudeDefaultVersion
 	}
-
 	headers.Set("anthropic-version", c.config.apiVersion)
+
+	// Check if Claude Code mode is enabled
+	if c.config.claudeCodeMode {
+		// Claude Code mode: use OAuth token with Bearer authorization
+		token := c.config.GetApiTokenInUse(ctx)
+		headers.Set("authorization", "Bearer "+token)
+		headers.Del("x-api-key")
+
+		// Set Claude Code specific headers
+		headers.Set("user-agent", claudeCodeUserAgent)
+		headers.Set("x-app", "cli")
+		headers.Set("anthropic-beta", claudeCodeBetaFeatures)
+
+		// Add ?beta=true query parameter to the path
+		currentPath := headers.Get(":path")
+		if currentPath != "" && !strings.Contains(currentPath, "beta=true") {
+			if strings.Contains(currentPath, "?") {
+				headers.Set(":path", currentPath+"&beta=true")
+			} else {
+				headers.Set(":path", currentPath+"?beta=true")
+			}
+		}
+	} else {
+		// Standard mode: use x-api-key
+		headers.Set("x-api-key", c.config.GetApiTokenInUse(ctx))
+	}
 }
 
 func (c *claudeProvider) OnRequestBody(ctx wrapper.HttpContext, apiName ApiName, body []byte) (types.Action, error) {
@@ -415,9 +442,25 @@ func (c *claudeProvider) buildClaudeTextGenRequest(origRequest *chatCompletionRe
 
 	for _, message := range origRequest.Messages {
 		if message.Role == roleSystem {
-			claudeRequest.System = &claudeSystemPrompt{
-				StringValue: message.StringContent(),
-				IsArray:     false,
+			// In Claude Code mode, use array format with cache_control
+			if c.config.claudeCodeMode {
+				claudeRequest.System = &claudeSystemPrompt{
+					ArrayValue: []claudeChatMessageContent{
+						{
+							Type: contentTypeText,
+							Text: message.StringContent(),
+							CacheControl: map[string]interface{}{
+								"type": "ephemeral",
+							},
+						},
+					},
+					IsArray: true,
+				}
+			} else {
+				claudeRequest.System = &claudeSystemPrompt{
+					StringValue: message.StringContent(),
+					IsArray:     false,
+				}
 			}
 			continue
 		}

plugins/wasm-go/extensions/ai-proxy/provider/provider.go

@@ -442,6 +442,9 @@ type ProviderConfig struct {
 	// @Title zh-CN 豆包服务域名
 	// @Description zh-CN 仅适用于豆包服务，默认转发域名为 ark.cn-beijing.volces.com
 	doubaoDomain string `required:"false" yaml:"doubaoDomain" json:"doubaoDomain"`
+	// @Title zh-CN Claude Code 模式
+	// @Description zh-CN 仅适用于Claude服务。启用后将伪装成Claude Code客户端发起请求，支持使用Claude Code的OAuth Token进行认证。
+	claudeCodeMode bool `required:"false" yaml:"claudeCodeMode" json:"claudeCodeMode"`
 }
 
 func (c *ProviderConfig) GetId() string {
@@ -646,6 +649,7 @@ func (c *ProviderConfig) FromJson(json gjson.Result) {
 	c.vllmServerHost = json.Get("vllmServerHost").String()
 	c.vllmCustomUrl = json.Get("vllmCustomUrl").String()
 	c.doubaoDomain = json.Get("doubaoDomain").String()
+	c.claudeCodeMode = json.Get("claudeCodeMode").Bool()
 	c.contextCleanupCommands = make([]string, 0)
 	for _, cmd := range json.Get("contextCleanupCommands").Array() {
 		if cmd.String() != "" {