add watchOS code from Workout+ to TODO for future reference

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

TODO/WorkoutPlusWatch/Views/ElapsedTimeView.swift

@@ -0,0 +1,47 @@
+import SwiftUI
+
+struct ElapsedTimeView: View {
+	var elapsedTime: TimeInterval = 0
+	var showSubseconds: Bool = true
+	@State private var timeFormatter = ElapsedTimeFormatter()
+
+	var body: some View {
+		Text(NSNumber(value: elapsedTime), formatter: timeFormatter)
+			.fontWeight(.semibold)
+			.onChange(of: showSubseconds) { _, newValue in
+				timeFormatter.showSubseconds = newValue
+			}
+	}
+}
+
+class ElapsedTimeFormatter: Formatter {
+	let componentsFormatter: DateComponentsFormatter = {
+		let formatter = DateComponentsFormatter()
+		formatter.allowedUnits = [.minute, .second]
+		formatter.zeroFormattingBehavior = .pad
+		return formatter
+	}()
+	var showSubseconds = true
+
+	override func string(for value: Any?) -> String? {
+		guard let time = value as? TimeInterval else {
+			return nil
+		}
+
+		guard let formattedString = componentsFormatter.string(from: time) else {
+			return nil
+		}
+
+		if showSubseconds {
+			let hundredths = Int((time.truncatingRemainder(dividingBy: 1)) * 100)
+			let decimalSeparator = Locale.current.decimalSeparator ?? "."
+			return String(format: "%@%@%0.2d", formattedString, decimalSeparator, hundredths)
+		}
+
+		return formattedString
+	}
+}
+
+#Preview {
+	ElapsedTimeView()
+}