chore(deps): expo-router 6 + register expo-font/expo-web-browser plugins

- expo-router 6 (per Phase 1 upgrade): all our imports remain valid
  (Stack, useLocalSearchParams, useRouter, useFocusEffect, withLayoutContext,
  RelativePathString). No `Href<T>` generic usage in codebase. expo-splash-screen
  already explicit in deps. Zero code changes needed for router-6 migration.
- Register expo-font + expo-web-browser as plugins per `expo install --fix`
  recommendation. Both already in deps but plugins block missing.

TS: 0 errors. Bundle still works.

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

apps/rebreak-native/app.config.ts

@@ -56,6 +56,8 @@ export default ({ config }: ConfigContext): ExpoConfig => ({
   plugins: [
     "expo-router",
     "expo-localization",
+    "expo-font",
+    "expo-web-browser",
     [
       "expo-build-properties",
       {