Introduced SKILL.md with a comprehensive workflow for auditing and improving SwiftUI runtime performance, including code review, profiling, diagnosis, and remediation steps. Added summarized Apple and WWDC resources under the references directory to support performance analysis and best practices.
Added a new reference file summarizing SwiftUI-specific concurrency guidance from WWDC, covering actor isolation, Sendable closures, and async work structuring. Updated SKILL.md to include a link to this new reference for easier access to SwiftUI concurrency best practices.
