implement settings

MultiChrono/ContentView.swift

@@ -53,6 +53,7 @@ class ContentViewModel: ObservableObject {
 struct ContentView: View {
     @StateObject private var viewModel = ContentViewModel()
     @State private var isShowingAddSheet = false
+    @State private var isShowingSettings = false
     @State private var selectedStopwatch: Stopwatch?
     @Environment(\.scenePhase) private var scenePhase
     
@@ -78,6 +79,13 @@ struct ContentView: View {
             .listStyle(.plain)
             .navigationTitle("MultiChrono")
             .toolbar {
+                ToolbarItem(placement: .topBarLeading) {
+                    Button {
+                        isShowingSettings = true
+                    } label: {
+                        Image(systemName: "gearshape")
+                    }
+                }
                 ToolbarItem(placement: .primaryAction) {
                     Button(action: {
                         isShowingAddSheet = true
@@ -92,6 +100,9 @@ struct ContentView: View {
                     isShowingAddSheet = false
                 }
             }
+            .sheet(isPresented: $isShowingSettings) {
+                SettingsView()
+            }
             .sheet(item: $selectedStopwatch) { stopwatch in
                 StopwatchDetailView(
                     stopwatch: stopwatch,
@@ -115,6 +126,7 @@ struct ContentView: View {
                 }
             }
         }
+
         .onChange(of: scenePhase) { newPhase in
             if newPhase == .background || newPhase == .inactive {
                 viewModel.save()