docs: add missing client-only hooks to RSC audit checklist

Add useLayoutEffect, useInsertionEffect, useImperativeHandle, and
useSyncExternalStore to the React hooks list and the audit grep
checklist. These hooks are client-only and would fail at runtime
with "hook is not a function" in a mis-classified Server Component.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: justin808

docs/pro/react-server-components/upgrading-existing-pro-app.md

@@ -38,7 +38,7 @@ Before running the generator, audit your existing components to identify which o
 
 Components that use any of the following **must** have `'use client'`:
 
-- **React hooks** (`import { ... } from 'react'`): `useState`, `useEffect`, `useContext`, `useRef`, `useReducer`, `useCallback`, `useMemo`, `useTransition`, `useDeferredValue`, `useId`, `useOptimistic`
+- **React hooks** (`import { ... } from 'react'`): `useState`, `useEffect`, `useLayoutEffect`, `useInsertionEffect`, `useContext`, `useRef`, `useImperativeHandle`, `useReducer`, `useCallback`, `useMemo`, `useTransition`, `useDeferredValue`, `useId`, `useSyncExternalStore`, `useOptimistic`
 - **React DOM hooks** (`import { ... } from 'react-dom'`): `useFormStatus`
 - **React on Rails client APIs**: `ReactOnRails.getStore()`, `ReactOnRails.authenticityToken()`
 - **Redux**: `useSelector`, `useDispatch`, `connect()`, `<Provider>`
@@ -71,7 +71,7 @@ There is no warning when a component is auto-classified as a server component. I
 
 Before proceeding to Step 1:
 
-- [ ] Search your component source files for `useState`, `useEffect`, `useContext`, `useRef`, `useReducer`, `useCallback`, `useMemo`, `useTransition`, `useDeferredValue`, `useId`, `useOptimistic`, `useFormStatus`, `useSelector`, `useDispatch`, `useNavigate`, `useLocation`, `useParams`, `ReactOnRails.getStore`, `ReactOnRails.authenticityToken`
+- [ ] Search your component source files for `useState`, `useEffect`, `useLayoutEffect`, `useInsertionEffect`, `useContext`, `useRef`, `useImperativeHandle`, `useReducer`, `useCallback`, `useMemo`, `useTransition`, `useDeferredValue`, `useId`, `useSyncExternalStore`, `useOptimistic`, `useFormStatus`, `useSelector`, `useDispatch`, `useNavigate`, `useLocation`, `useParams`, `ReactOnRails.getStore`, `ReactOnRails.authenticityToken`
 - [ ] Check all `.server.jsx` files -- these almost certainly need `'use client'`
 - [ ] Check components that use `StaticRouter` (SSR wrapper, not a client API — but the file likely uses other client APIs)
 - [ ] Verify no component relies on browser globals (`window`, `document`) without `'use client'`