Added gemfile and updated podfile.lock

[MeliValesca]

Summary

The iOS example app could not be set up following the documented steps (bundle install → yarn ios) because:

1. The Gemfile was missing from the example/ directory, causing bundle install and react-native run-ios to fail.
2. The Podfile.lock was stale and had dependency versions (e.g. fmt) that conflicted with react-native 0.80.1, causing pod install to fail.

This adds a Gemfile with cocoapods pinned to ~> 1.16 and CFPropertyList pinned to 3.0.7 (for Ruby 3.4 compatibility), and removes the stale Podfile.lock so it gets regenerated fresh on pod install.

Test Plan

Followed the contributing docs from a clean state:

cd example
yarn install
bundle install

cd ios && bundle exec pod install

cd .. && yarn ios

[janicduplessis]

🚀