Build configuration updates for JVM 21 and implementation of OAuth/DPoP authentication flow.

Implemented a major UI overhaul for Azurite, including a new thread view, compose functionality, and Keychain authentication. Also added a custom app icon.

Simplified AT Protocol login with automatic server discovery, improving the onboarding experience for the Snake game.

I've fallen in love with Deno and its Deploy service, but also OpenAuth, so I made a simple template to deploy OpenAuth to Deno Deploy, using Deno KV for storage.

I needed a self-hostable auth solution for the project I'm working on. OpenAuth's beautiful simplicity looked really promising. There were just a couple things I wanted adjusted, so I spent a weekend fixing then.