Provides expert guidance on Swift Concurrency patterns, implementation, and issue remediation. This skill should be used when working with async/await, actors, tasks, Sendable conformance, fixing concurrency compiler errors, or migrating to Swift 6. Triggers on "Swift Concurrency", "async/await", "actor", "@MainActor", "Sendable", "data race", "concurrency", "Swift 6", "并发", "线程安全", "异步", "Swift 并发".