Multiplayer

The game could use a multiplayer function to allow users to play against human players without the need for proximity or hot seating.

This would require a new class to represent network tanks as well as some new base code for communicating over the network.

A chat would also be in order.

- [ ] Network communication
- [ ] Updating tanks using information from network
- [ ] Failsafes for when players lag out
- [ ] Chat system (requires addition to UI)

The issue does not name files, tests, or an entry point. Start by mapping the existing Swift game structure and how multiplayer would fit alongside network communication, network tanks, lag-out handling, and chat. Done means human players can play remotely with tank updates, failure handling, and an in-game chat system.

Written by the indexing model from the issue text.