Initial scaffold — NASBackup iOS app

Full project scaffold: XcodeGen project.yml, Core models/protocols/errors,
SMBService (kishikawakatsumi/SMBClient), SFTPService (Citadel 0.9.2),
PhotoLibraryService, LANMonitor, BackupEngine, BackgroundTaskManager,
all feature UIs (Login, Connect, Browse, Backup, History, Settings),
Shared components and theme. Builds clean with zero errors.

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

App/NASBackupApp.swift

@@ -0,0 +1,31 @@
+import SwiftUI
+
+@main
+struct NASBackupApp: App {
+    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
+
+    @StateObject private var store = ConnectionStore.shared
+    @StateObject private var engine = BackupEngine.shared
+    @StateObject private var lanMonitor = LANMonitor.shared
+
+    var body: some Scene {
+        WindowGroup {
+            RootView()
+                .environmentObject(store)
+                .environmentObject(engine)
+                .environmentObject(lanMonitor)
+        }
+    }
+}
+
+struct RootView: View {
+    @EnvironmentObject var store: ConnectionStore
+
+    var body: some View {
+        if store.savedConnection != nil {
+            LoginView()
+        } else {
+            ConnectView()
+        }
+    }
+}