stub out react-native-svg fetchData on web to drop buffer polyfill

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

webpack.config.js

@@ -1,3 +1,5 @@
+const path = require('path')
+
 const createExpoWebpackConfigAsync = require('@expo/webpack-config')
 const {withAlias} = require('@expo/webpack-config/addons')
 const ReactRefreshWebpackPlugin = require('@pmmmwh/react-refresh-webpack-plugin')
@@ -46,11 +48,34 @@ module.exports = async function (env, argv) {
     dangerouslyAddModulePathsToTranspile: ['@bsky.app/expo', '@atproto/api'],
   }
   let config = await createExpoWebpackConfigAsync(env, argv)
+  /*
+   * Expo only registers its own internal config as a cache build dependency,
+   * so changes to this file (e.g. aliases) don't invalidate the persistent
+   * filesystem cache and stale module resolutions get reused. Register this
+   * file so edits here always bust the cache.
+   */
+  if (config.cache?.buildDependencies) {
+    config.cache.buildDependencies.config = [
+      ...(config.cache.buildDependencies.config || []),
+      __filename,
+    ]
+  }
   config = withAlias(config, {
     'react-native$': 'react-native-web',
     'react-native-webview': 'react-native-web-webview',
     'react-native-gesture-handler': false, // RNGH should not be used on web, so let's cause a build error if it sneaks in
     '@sentry-internal/replay': false, // not used, ~300kb of dead weight
+    /*
+     * react-native-svg's fetchData util imports the ~55KB `buffer` polyfill,
+     * but is only needed by SvgUri/SvgXml remote loading, which we don't use.
+     * Stubbing it out makes fetchText undefined, so it throws if ever called.
+     * The alias key must be an absolute path because the package imports it
+     * via a relative path internally.
+     */
+    [path.join(
+      __dirname,
+      'node_modules/react-native-svg/lib/module/utils/fetchData',
+    )]: false,
   })
 
   // react-native-uuid ships sourceMappingURL comments but no .map files.