Add React Native mobile app for opencode

[nitishxyz]

Summary

• Add comprehensive React Native mobile application with Expo framework • Implement chat interface with real-time messaging and session management
• Integrate with opencode API for seamless mobile access to AI assistant functionality • Add README with instructions to run the app.

More Info

• This is a work in progress, a lot of performance optimizations are to be made.
• Some dumb decisions were also made with or without the help of ai, so have to fix them yet.
• one thing i missed to add was multiple servers, as i missed to relate serverIds to the sessions, which would allow to switch servers. (will work on it next maybe)

What is done

• Connecting to a server
• Listing sessions
• Creating new sessions
• Response streaming
• Markdown rendering
• Costs
• Tool call specific UI
• Swipe up to switch mode (plan, build)

[nitishxyz]

Mobile App Updates

• Projects (different servers) • Project deletion • Settings page with theme toggle • Welcome screen for new users • Session cost & token tracking • Skeleton loaders • Direct database streaming • Bottom sheet inputs • Real-time connection status • Enhanced performance optimizations