feat(test-expo): add Expo Router example with a route per package

[russellwheatley]

• Fixes 🔥 [iOS][SPM][Crashlytics] dSYM upload-symbols script hardcodes ${PROJECT_DIR}/GoogleService-Info.plist, ignoring Expo/target-folder location #9304

Turns workspace test-expo/ into a user-facing Expo Router example (one route per included package, Auth as the only full flow) while keeping yarn test-expo:ios:link as the documented-path iOS closer on the widened native graph.

• Expo Router TypeScript shell, Android placeholder google services, remaining inventory deps and plugins
• Generic RNFB* framework closer, with the named App+Messaging signatures nested
• Email/anonymous Auth plus thin modular screens for the rest of the inventory
• Crashlytics SPM upload-symbols finds the plist under Expo/RN CLI target-folder layout, and a rejected upload warns instead of failing the build
• OKF records test-expo/ as the full-package example; usage pages and Getting Started permalink the routes

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Maintainer note: Fixes internal CPRN-317

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 69.06%. Comparing base (695161f) to head (6b5f218).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #9313      +/-   ##
============================================
- Coverage     69.49%   69.06%   -0.43%     
  Complexity     2129     2129              
============================================
  Files           439      437       -2     
  Lines         25472    25113     -359     
  Branches       4251     4251              
============================================
- Hits          17700    17341     -359     
  Misses         6365     6365              
  Partials       1407     1407              

Flag	Coverage Δ
android-native	65.92% <ø> (ø)
e2e-ts-android	54.44% <ø> (ø)
e2e-ts-ios	53.91% <ø> (ø)
e2e-ts-macos	49.96% <ø> (ø)
ios-ruby	?
jest	47.57% <ø> (ø)

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