feat(thinking): add xAI provider support with reasoning.effort implementation

- Implemented `xAI` provider for thinking configurations with support for reasoning.effort levels.
- Registered `xAI` in available providers and updated relevant APIs for compatibility.
- Added unit tests for `xAI` provider functionality, including fallback logic for unsupported levels.
- Integrated `xAI` with executor handling and ensured conformance with OpenAI-compatible standards.

internal/runtime/executor/helps/thinking_providers.go

@@ -8,4 +8,5 @@ import (
 	_ "github.com/router-for-me/CLIProxyAPI/v7/internal/thinking/provider/geminicli"
 	_ "github.com/router-for-me/CLIProxyAPI/v7/internal/thinking/provider/kimi"
 	_ "github.com/router-for-me/CLIProxyAPI/v7/internal/thinking/provider/openai"
+	_ "github.com/router-for-me/CLIProxyAPI/v7/internal/thinking/provider/xai"
 )

internal/runtime/executor/xai_executor.go

@@ -487,7 +487,7 @@ func (e *XAIExecutor) prepareResponsesRequest(ctx context.Context, req cliproxye
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), stream)
 
 	var err error
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), e.Identifier(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}

internal/runtime/executor/xai_executor_test.go

@@ -196,6 +196,48 @@ func TestXAIExecutorOmitsUnsupportedReasoningEffort(t *testing.T) {
 	}
 }
 
+func TestXAIExecutorAppliesThinkingSuffix(t *testing.T) {
+	var gotBody []byte
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var errRead error
+		gotBody, errRead = io.ReadAll(r.Body)
+		if errRead != nil {
+			t.Fatalf("read body: %v", errRead)
+		}
+		w.Header().Set("Content-Type", "text/event-stream")
+		_, _ = w.Write([]byte("data: {\"type\":\"response.completed\",\"response\":{\"id\":\"resp_1\",\"object\":\"response\",\"created_at\":0,\"status\":\"completed\",\"model\":\"grok-4.3\",\"output\":[{\"type\":\"message\",\"role\":\"assistant\",\"content\":[{\"type\":\"output_text\",\"text\":\"ok\"}]}]}}\n\n"))
+	}))
+	defer server.Close()
+
+	exec := NewXAIExecutor(&config.Config{})
+	auth := &cliproxyauth.Auth{
+		Provider: "xai",
+		Attributes: map[string]string{
+			"base_url":  server.URL,
+			"auth_kind": "oauth",
+		},
+		Metadata: map[string]any{"access_token": "xai-token"},
+	}
+
+	_, err := exec.Execute(context.Background(), auth, cliproxyexecutor.Request{
+		Model:   "grok-4.3(low)",
+		Payload: []byte(`{"model":"grok-4.3","input":"hello"}`),
+	}, cliproxyexecutor.Options{
+		SourceFormat: sdktranslator.FormatOpenAIResponse,
+		Stream:       false,
+	})
+	if err != nil {
+		t.Fatalf("Execute() error = %v", err)
+	}
+
+	if got := gjson.GetBytes(gotBody, "model").String(); got != "grok-4.3" {
+		t.Fatalf("model = %q, want grok-4.3; body=%s", got, string(gotBody))
+	}
+	if got := gjson.GetBytes(gotBody, "reasoning.effort").String(); got != "low" {
+		t.Fatalf("reasoning.effort = %q, want low; body=%s", got, string(gotBody))
+	}
+}
+
 func TestXAIExecutorExecuteStreamFiltersToolSearchTool(t *testing.T) {
 	var gotBody []byte
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {