Complete platform migration replacing React Native/Expo implementation with Flutter. This is a 1:1 recreation of functionality with improved native platform support and better OAuth integration. Key changes: - Replaced React Native/Expo with Flutter framework - Migrated atProto OAuth authentication to Flutter - Implemented custom atproto_oauth_flutter package - Updated Android and iOS platform-specific configurations - Migrated all screens: landing, login, feed - Updated .gitignore to exclude Flutter build artifacts - Preserved git history on flutter-migration branch The React Native implementation remains accessible on the main branch for reference. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>