Add Tonuino Manager website and Sparkle updates

Sources/TonuinoManager/App/AppModel.swift

@@ -0,0 +1,40 @@
+import AppKit
+import Combine
+import SwiftUI
+
+@MainActor
+final class AppModel: ObservableObject {
+    enum Section: String, CaseIterable, Identifiable, Hashable {
+        case library = "SD-Karte"
+        case cards = "NFC-Karten"
+        case tonuino = "TonUINO"
+        case settings = "Einstellungen"
+        var id: String { rawValue }
+        var icon: String {
+            switch self {
+            case .library: "sdcard"
+            case .cards: "wave.3.right"
+            case .tonuino: "slider.horizontal.3"
+            case .settings: "gearshape"
+            }
+        }
+    }
+
+    @Published var section: Section = .library
+    @Published var library = LibraryModel()
+    @Published var cards = CardModel()
+    @Published var status = "Bereit"
+    @Published var errorMessage: String?
+    @Published var showError = false
+    private var childSubscriptions = Set<AnyCancellable>()
+
+    init() {
+        library.objectWillChange.sink { [weak self] _ in self?.objectWillChange.send() }.store(in: &childSubscriptions)
+        cards.objectWillChange.sink { [weak self] _ in self?.objectWillChange.send() }.store(in: &childSubscriptions)
+    }
+
+    func report(_ error: Error) {
+        errorMessage = error.localizedDescription
+        showError = true
+    }
+}