Fix React 18.0.0 compatibility by using React namespace imports

Changed from named imports to React namespace for better compatibility with React 18.0.0:
- `Component` → `React.Component`
- `createContext` → `React.createContext`
- `useContext` → `React.useContext`
- `use` → `React.use`

This fixes the build (20) CI failure where React is downgraded to 18.0.0 for
minimum version testing. Named exports may not be available in older React versions.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

packages/react-on-rails-pro/src/RSCProvider.tsx

@@ -15,7 +15,7 @@
 'use client';
 
 import * as React from 'react';
-import { createContext, useContext, type ReactNode } from 'react';
+import { type ReactNode } from 'react';
 import type { ClientGetReactServerComponentProps } from './getReactServerComponent.client.ts';
 import { createRSCPayloadKey } from './utils.ts';
 
@@ -25,7 +25,7 @@ type RSCContextType = {
   refetchComponent: (componentName: string, componentProps: unknown) => Promise<ReactNode>;
 };
 
-const RSCContext = createContext<RSCContextType | undefined>(undefined);
+const RSCContext = React.createContext<RSCContextType | undefined>(undefined);
 
 /**
  * Creates a provider context for React Server Components.
@@ -102,7 +102,7 @@ export const createRSCProvider = ({
  * ```
  */
 export const useRSC = () => {
-  const context = useContext(RSCContext);
+  const context = React.useContext(RSCContext);
   if (!context) {
     throw new Error('useRSC must be used within a RSCProvider');
   }

packages/react-on-rails-pro/src/RSCRoute.tsx

@@ -17,15 +17,15 @@
 'use client';
 
 import * as React from 'react';
-import { Component, use, type ReactNode } from 'react';
+import { type ReactNode } from 'react';
 import { useRSC } from './RSCProvider.tsx';
 import { ServerComponentFetchError } from './ServerComponentFetchError.ts';
 
 /**
  * Error boundary component for RSCRoute that adds server component name and props to the error
  * So, the parent ErrorBoundary can refetch the server component
  */
-class RSCRouteErrorBoundary extends Component<
+class RSCRouteErrorBoundary extends React.Component<
   { children: ReactNode; componentName: string; componentProps: unknown },
   { error: Error | null }
 > {
@@ -77,8 +77,8 @@ export type RSCRouteProps = {
 };
 
 const PromiseWrapper = ({ promise }: { promise: Promise<ReactNode> }) => {
-  // use is available in React 18.3+
-  const promiseResult = use(promise);
+  // React.use is available in React 18.3+
+  const promiseResult = React.use(promise);
 
   // In case that an error happened during the rendering of the RSC payload before the rendering of the component itself starts
   // RSC bundle will return an error object serialized inside the RSC payload