Remove git dependency

[Clydingus]

Fixes #16. uv sync successful with following:

Resolved 78 packages in 9.10s
      Built world-engine @ https://github.com/Wayfarer-Labs/world_engine/archive/refs/heads/websocket.zip
Prepared 1 package in 3.27s
Uninstalled 2 packages in 62ms
Installed 1 package in 13ms
 - timm==1.0.24
 - world-engine==0.0.3 (from git+https://github.com/Wayfarer-Labs/world_engine.git@ff4be4e69c66777d2b2177a67299131d72d31a24)
 + world-engine==0.0.3 (from https://github.com/Wayfarer-Labs/world_engine/archive/refs/heads/websocket.zip)