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>

Services/LANMonitor.swift

@@ -0,0 +1,59 @@
+import Foundation
+import Network
+import NetworkExtension
+import Combine
+
+@MainActor
+final class LANMonitor: ObservableObject {
+    static let shared = LANMonitor()
+
+    @Published private(set) var isOnNetwork: Bool = false
+    @Published private(set) var currentSSID: String? = nil
+
+    private let monitor = NWPathMonitor()
+    private let queue = DispatchQueue(label: "com.albert.nasbackup.lan", qos: .utility)
+
+    var onTrustedNetworkJoined: ((String) -> Void)?
+
+    private init() {}
+
+    func start() {
+        monitor.pathUpdateHandler = { [weak self] path in
+            guard let self else { return }
+            Task { @MainActor in
+                let satisfied = path.status == .satisfied
+                self.isOnNetwork = satisfied
+
+                if satisfied {
+                    await self.checkSSID()
+                } else {
+                    self.currentSSID = nil
+                }
+            }
+        }
+        monitor.start(queue: queue)
+    }
+
+    func stop() {
+        monitor.cancel()
+    }
+
+    private func checkSSID() async {
+        let ssid = await fetchCurrentSSID()
+        self.currentSSID = ssid
+    }
+
+    func fetchCurrentSSID() async -> String? {
+        await withCheckedContinuation { continuation in
+            NEHotspotNetwork.fetchCurrent { network in
+                continuation.resume(returning: network?.ssid)
+            }
+        }
+    }
+
+    func checkAndTriggerIfTrusted(trustedSSIDs: [String]) async {
+        let ssid = await fetchCurrentSSID()
+        guard let ssid, trustedSSIDs.contains(ssid) else { return }
+        onTrustedNetworkJoined?(ssid)
+    }
+}