Use a module request for asyncRequireModulePath so Metro's transform cache is shareable across checkouts

@react-native/metro-config set asyncRequireModulePath with require.resolve(),
which embeds the absolute path of the checkout in Metro's global transform
cache key. Two checkouts of the same project (git worktrees, CI workspaces)
never shared a transform cache entry. Use the bare specifier, matching Metro's
own default and @expo/metro-config, with an extraNodeModules fallback so it
still resolves in installs where metro-runtime is not reachable from every
module (pnpm isolated).

Author: janicduplessis

packages/metro-config/src/index.flow.js

@@ -11,6 +11,7 @@
 import type {ConfigT, InputConfigT} from 'metro-config';
 
 import {getDefaultConfig as getBaseConfig, mergeConfig} from 'metro-config';
+import path from 'node:path';
 
 export type {MetroConfig} from 'metro-config';
 
@@ -57,6 +58,14 @@ export function getDefaultConfig(projectRoot: string): ConfigT {
       resolverMainFields: ['react-native', 'browser', 'main'],
       platforms: ['android', 'ios'],
       unstable_conditionNames: ['react-native'],
+      // Lets transformer.asyncRequireModulePath stay a module request, which
+      // keeps it out of the transform cache key, in installs where
+      // metro-runtime is not reachable from every module (pnpm isolated).
+      extraNodeModules: {
+        'metro-runtime': path.dirname(
+          require.resolve('metro-runtime/package.json'),
+        ),
+      },
     },
     serializer: {
       // NOTE: Overridden in community-cli-plugin
@@ -85,8 +94,7 @@ export function getDefaultConfig(projectRoot: string): ConfigT {
     transformer: {
       allowOptionalDependencies: true,
       assetRegistryPath: 'react-native/asset-registry',
-      asyncRequireModulePath:
-        require.resolve('metro-runtime/src/modules/asyncRequire'),
+      asyncRequireModulePath: 'metro-runtime/src/modules/asyncRequire',
       babelTransformerPath:
         require.resolve('@react-native/metro-babel-transformer'),
       getTransformOptions: async () => ({