fix(openai): detect official codex client by headers

backend/internal/service/openai_gateway_service_test.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
 	"github.com/cespare/xxhash/v2"
 	"github.com/gin-gonic/gin"
 	"github.com/stretchr/testify/require"
@@ -1372,6 +1373,46 @@ func TestOpenAIBuildUpstreamRequestPreservesCompactPathForAPIKeyBaseURL(t *testi
 	require.Equal(t, "https://example.com/v1/responses/compact", req.URL.String())
 }
 
+func TestOpenAIBuildUpstreamRequestOAuthOfficialClientOriginatorCompatibility(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	tests := []struct {
+		name           string
+		userAgent      string
+		originator     string
+		wantOriginator string
+	}{
+		{name: "desktop originator preserved", originator: "Codex Desktop", wantOriginator: "Codex Desktop"},
+		{name: "vscode originator preserved", originator: "codex_vscode", wantOriginator: "codex_vscode"},
+		{name: "official ua fallback to codex_cli_rs", userAgent: "Codex Desktop/1.2.3", wantOriginator: "codex_cli_rs"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			rec := httptest.NewRecorder()
+			c, _ := gin.CreateTestContext(rec)
+			c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses", bytes.NewReader([]byte(`{"model":"gpt-5"}`)))
+			if tt.userAgent != "" {
+				c.Request.Header.Set("User-Agent", tt.userAgent)
+			}
+			if tt.originator != "" {
+				c.Request.Header.Set("originator", tt.originator)
+			}
+
+			svc := &OpenAIGatewayService{}
+			account := &Account{
+				Type:        AccountTypeOAuth,
+				Credentials: map[string]any{"chatgpt_account_id": "chatgpt-acc"},
+			}
+
+			isCodexCLI := openai.IsCodexOfficialClientByHeaders(c.GetHeader("User-Agent"), c.GetHeader("originator"))
+			req, err := svc.buildUpstreamRequest(c.Request.Context(), c, account, []byte(`{"model":"gpt-5"}`), "token", false, "", isCodexCLI)
+			require.NoError(t, err)
+			require.Equal(t, tt.wantOriginator, req.Header.Get("originator"))
+		})
+	}
+}
+
 // ==================== P1-08 修复：model 替换性能优化测试 ====================
 
 // ==================== P1-08 修复：model 替换性能优化测试 =============