Installing simulator runtimes from the command line – Donny Wals

When the Xcode GUI fails to download iOS simulator runtimes (stuck on 'fetching download information'), you can use the command line instead. Running `xcodebuild -downloadPlatform iOS` works in most cases, but if it reports 'No matching downloadable found', you need to explicitly specify the architecture variant with `xcodebuild -downloadPlatform iOS -architectureVariant arm64`. To download all platforms at once, use `xcodebuild -downloadAllPlatforms -architectureVariant arm64`. Make sure the correct Xcode version is selected via `xcode-select` before running these commands.