Fix composite Grok video status routing

backend/internal/server/routes/gateway.go

@@ -106,7 +106,10 @@ func RegisterGatewayRoutes(
 		})
 	}
 	videoStatusHandler := func(c *gin.Context) {
-		if getGroupPlatform(c) == service.PlatformGrok {
+		// Video status requests do not carry a model, so composite groups cannot
+		// be resolved by compositeTargetPlatformMiddleware. Route them through
+		// the Grok handler and let scheduler/account selection enforce capacity.
+		if getGroupPlatform(c) == service.PlatformGrok || getGroupPlatform(c) == service.PlatformComposite {
 			h.OpenAIGateway.GrokVideoStatus(c)
 			return
 		}

backend/internal/server/routes/gateway_test.go

@@ -177,6 +177,22 @@ func TestGatewayRoutesGrokImagesAndVideosPathsAreRegistered(t *testing.T) {
 	}
 }
 
+func TestGatewayRoutesCompositeVideoStatusUsesGrokHandler(t *testing.T) {
+	router := newGatewayRoutesTestRouter(service.PlatformComposite)
+
+	for _, path := range []string{
+		"/v1/videos/request-123",
+		"/videos/request-123",
+	} {
+		req := httptest.NewRequest(http.MethodGet, path, nil)
+		w := httptest.NewRecorder()
+
+		router.ServeHTTP(w, req)
+		require.NotEqual(t, http.StatusNotFound, w.Code, "path=%s should hit Grok video status handler", path)
+		require.NotContains(t, w.Body.String(), "not supported for this platform")
+	}
+}
+
 func TestGatewayRoutesNonGrokVideosAreRejectedAtPlatformGate(t *testing.T) {
 	router := newGatewayRoutesTestRouter(service.PlatformOpenAI)