implement settings

MultiChrono/AppSettings.swift

@@ -0,0 +1,33 @@
+//
+//  AppSettings.swift
+//  MultiChrono
+//
+//  Created by Beatrice Dellacà on 27/01/26.
+//
+
+import Foundation
+import Combine
+
+enum TimeFormat: String, CaseIterable, Codable {
+    case millis   = "Millis (00:00.000)"
+    case cents    = "Cents (00:00.00)"
+    case tenths   = "Tenths (00:00.0)"
+    case seconds  = "Seconds (00:00)"
+    
+    var displayName: String { self.rawValue }
+}
+
+class AppSettings: ObservableObject {
+    static let shared = AppSettings()
+    
+    @Published var timeFormat: TimeFormat {
+        didSet {
+            UserDefaults.standard.set(timeFormat.rawValue, forKey: "timeFormat")
+        }
+    }
+    
+    private init() {
+        let savedFormat = UserDefaults.standard.string(forKey: "timeFormat") ?? TimeFormat.tenths.rawValue
+        self.timeFormat = TimeFormat(rawValue: savedFormat) ?? .tenths
+    }
+}