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>

Core/Protocols/NASTransferProtocol.swift

@@ -0,0 +1,25 @@
+import Foundation
+
+struct NASItem: Identifiable {
+    let id = UUID()
+    let name: String
+    let path: String
+    let isDirectory: Bool
+    let size: Int64
+    let modifiedDate: Date?
+}
+
+protocol NASTransferProtocol: AnyObject {
+    var isConnected: Bool { get }
+
+    func connect(to host: String, port: Int, username: String, password: String) async throws
+    func disconnect()
+    func listDirectory(at path: String) async throws -> [NASItem]
+    func createDirectory(at path: String) async throws
+    func fileExists(at remotePath: String) async throws -> Bool
+    func upload(
+        localURL: URL,
+        remotePath: String,
+        progress: @escaping (Int64, Int64) -> Void
+    ) async throws
+}

Core/Protocols/PhotoLibraryProtocol.swift

@@ -0,0 +1,29 @@
+import Foundation
+import Photos
+
+struct PhotoAsset {
+    let localIdentifier: String
+    let filename: String
+    let creationDate: Date?
+    let mediaType: PHAssetMediaType
+    let pixelWidth: Int
+    let pixelHeight: Int
+    let duration: TimeInterval
+    let isScreenshot: Bool
+    let isRAW: Bool
+}
+
+protocol PhotoLibraryProtocol: AnyObject {
+    var authorizationStatus: PHAuthorizationStatus { get }
+    func requestAuthorization() async -> PHAuthorizationStatus
+    func fetchAssets(filter: BackupFilter) -> [PhotoAsset]
+    func exportAsset(_ asset: PhotoAsset) async throws -> URL
+}
+
+struct BackupFilter: Codable {
+    var includePhotos: Bool = true
+    var includeVideos: Bool = true
+    var includeScreenshots: Bool = false
+    var includeRAW: Bool = false
+    var newFilesOnly: Bool = true
+}