docs(cndocs): remove React.useState/useRef prefix in new-architecture docs (#1036)

- custom-cxx-types.md: React.useState → useState (5 occurrences)
- layout-measurements.md: React.useRef → useRef (1 occurrence)

Aligns with upstream React import removal pattern (React 17+ JSX transform).

Author: sunnylqm

cndocs/the-new-architecture/custom-cxx-types.md

@@ -173,8 +173,8 @@ First, we need to update the `App.tsx` file to use the new method from the Turbo
 
 ```diff title="App.tsx"
 // ...
-+ const [cubicSource, setCubicSource] = React.useState('')
-+ const [cubicRoot, setCubicRoot] = React.useState(0)
++ const [cubicSource, setCubicSource] = useState('')
++ const [cubicRoot, setCubicRoot] = useState(0)
   return (
     <SafeAreaView style={styles.container}>
       <View>
@@ -366,9 +366,9 @@ To test the code in the app, we have to modify the `App.tsx` file.
 2. Replace the body of the `App()` function with the following code:
 
 ```tsx title="App.tsx (App function body replacement)"
-const [street, setStreet] = React.useState('');
-const [num, setNum] = React.useState('');
-const [isValidAddress, setIsValidAddress] = React.useState<
+const [street, setStreet] = useState('');
+const [num, setNum] = useState('');
+const [isValidAddress, setIsValidAddress] = useState<
   boolean | null
 >(null);
 

cndocs/the-new-architecture/layout-measurements.md

@@ -10,7 +10,7 @@ Typical code will look like this:
 
 ```tsx
 function AComponent(children) {
-  const targetRef = React.useRef(null)
+  const targetRef = useRef(null)
 
   useLayoutEffect(() => {
     targetRef.current?.measure((x, y, width, height, pageX, pageY) => {