pnpm's strict isolated dependency resolution prevents @babel/core from
finding babel-preset-expo and @babel/plugin-transform-react-jsx during
Metro bundling. The pre-install hook creates .npmrc with node-linker=hoisted
at the monorepo root so pnpm uses a flat node_modules on EAS Build.
Also simplified metro.config.js by removing manual monorepo watchFolders
config (handled automatically by expo/metro-config since SDK 52).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>