Set up your Mac

iOS development needs a Mac and three tools, all free:

Xcode — Apple's IDE. It compiles Swift, runs the iPhone Simulator, and ships apps. It's a big download (~10 GB), so start it first.
Homebrew — the package manager for macOS, used to install command-line tools.
XcodeGen — generates the Xcode project file from apps/ios/project.yml. This repo uses it so the project file never causes git conflicts.

The backend also needs uv (a fast Python package manager) — one install command and you're done.