permissionlesstech/bitchat ? reverse-engineered prompt

I want to build a decentralized chat app for iOS and macOS. The core idea is that it works both offline and online. For offline, it should use Bluetooth to create a local mesh network. People nearby can chat directly, and their messages can hop between phones to reach others in the area, even with no internet. This would be great for events or emergencies.

Then, for long-distance communication, it should use the Nostr protocol to connect to a global network. I like the idea of creating location-based chat rooms based on geohashes, so you can have channels for a specific city block, a neighborhood, or a whole country.

The whole thing must be private—no phone numbers, no user accounts, and strong end-to-end encryption. Let's give it an old-school IRC vibe with slash commands like /msg. It should be a native Swift app that can run on both iPhones and Macs.