CI: run SwiftFormat through hk - #13

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: mxcl/xcodebuild@v3, nick-fields/retry@v3. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

'init(leadingTrivia:specifier:name:equal:expression:trailingComma:trailingTrivia:)' is deprecated: Use 'init(leadingTrivia:_:specifier:_:name:_:initializer:_:trailingComma:_:trailingTrivia:)' instead

'init(leadingTrivia:specifier:name:equal:expression:trailingComma:trailingTrivia:)' is deprecated: Use 'init(leadingTrivia:_:specifier:_:name:_:initializer:_:trailingComma:_:trailingTrivia:)' instead

'init(leadingTrivia:specifier:name:equal:expression:trailingComma:trailingTrivia:)' is deprecated: Use 'init(leadingTrivia:_:specifier:_:name:_:initializer:_:trailingComma:_:trailingTrivia:)' instead

'init(leadingTrivia:specifier:name:equal:expression:trailingComma:trailingTrivia:)' is deprecated: Use 'init(leadingTrivia:_:specifier:_:name:_:initializer:_:trailingComma:_:trailingTrivia:)' instead

xcodebuild: 2026-09-02 16:43:04.574 xcodebuild[4193:17252] [MT] IDERunDestination: Supported platforms for the buildables in the current scheme is empty.

xcodebuild: 2026-09-02 16:43:04.360 xcodebuild[4193:17252] [MT] IDERunDestination: Supported platforms for the buildables in the current scheme is empty.

xcodebuild: 2026-09-02 16:42:28.564 xcodebuild[2550:12226] [MT] IDERunDestination: Supported platforms for the buildables in the current scheme is empty.

xcodebuild: 2026-09-02 16:42:20.257 xcodebuild[2550:12226] [MT] IDERunDestination: Supported platforms for the buildables in the current scheme is empty.