fix: prevent speed change when no action sphere is selected in VehicleMechanics

app/src/components/layout/sidebarRight/mechanics/VehicleMechanics.tsx

@@ -62,7 +62,22 @@ const VehicleMechanics: React.FC = () => {
     }, [handleActionUpdate]);
 
     const handleSpeedChange = React.useCallback((speed: number) => {
-        
+        if (!selectedActionSphere?.point?.uuid) return;
+
+        const updatedPaths = simulationPaths.map((path) => {
+            if (path.type === "Vehicle" && path.point.uuid === selectedActionSphere.point.uuid) {
+                return {
+                    ...path,
+                    point: {
+                        ...path.point,
+                        speed: speed
+                    }
+                };
+            }
+            return path;
+        });
+
+        setSimulationPaths(updatedPaths);
     }, [selectedActionSphere?.point?.uuid, simulationPaths, setSimulationPaths]);
 
     return (