Swift: URLError stored as Error reports NSError via type(of:)

If you build a log-safe failure reason from type(of: error) or a switch over error types, a URLError held as any Error can report 'NSError', because it bridges. Match it explicitly with case let e as URLError (or is URLError) before any generic fallback. Map only .timedOut to 'timeout'; lumping every URLError together mislabels connection-refused and DNS failures. A mutation test that swaps the mapping catches the mistake.