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>

Shared/Components/ProgressRing.swift

@@ -0,0 +1,26 @@
+import SwiftUI
+
+struct ProgressRing: View {
+    let progress: Double
+    var lineWidth: CGFloat = 14
+    var size: CGFloat = 200
+    var color: Color = AppTheme.blue
+    var backgroundColor: Color = Color(hex: "#E5E7EB")
+
+    var body: some View {
+        ZStack {
+            Circle()
+                .stroke(backgroundColor, lineWidth: lineWidth)
+
+            Circle()
+                .trim(from: 0, to: CGFloat(min(progress, 1.0)))
+                .stroke(
+                    color,
+                    style: StrokeStyle(lineWidth: lineWidth, lineCap: .round)
+                )
+                .rotationEffect(.degrees(-90))
+                .animation(.easeInOut(duration: 0.4), value: progress)
+        }
+        .frame(width: size, height: size)
+    }
+}