feat: Kisani rebrand, step-based onboarding flow, dark mode fixes

- Rename app to Kisani in all UI text and Face ID prompt
- Replace flat 2-state RootView with 5-step flow: ConnectView →
  LoginView → FolderSetupView → PhotoPermissionView → MainTabView
- Remove NavigationStack from LoginView (was causing nested-stack crash);
  drive navigation via ConnectionStore.isSessionActive
- Add FolderSetupView and PhotoPermissionView onboarding screens with
  step indicator (2/3, 3/3), spring entrance animations, and UGreen
  connection chip
- Fix dark mode button invisibility: PrimaryButtonStyle and PillButtonStyle
  now use AppTheme.inkInverse; GhostButtonStyle border uses ink.opacity(0.25)
- Add AppTheme.inkInverse adaptive token (dark bg ink on dark, white on light)
- Add ConnectionStore.isSessionActive (non-persisted) and
  onboardingPhotoShown (UserDefaults-persisted)
- Add os_log logging in LoginViewModel at auth start/success/failure
- Remove dead Help button from ConnectView
- UGreenCompatibilityBadge, KeychainStore, SavedConnections, extensions,
  PrivacyInfo.xcprivacy, unit test target and test stubs
- AppTheme: full UIColor dynamic provider tokens for dark/light adaptive color
- AppearanceMode enum + segmented picker in SettingsView
- BackupView: enlarged ring, removed options card and linear progress bar
- HistoryView: duration and bytes formatting, improved typography hierarchy

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

Shared/Components/UGreenCompatibilityBadge.swift

@@ -0,0 +1,46 @@
+import SwiftUI
+import UIKit
+
+// Displays the UGreen NAS compatibility indicator.
+// If you add an image named "ugreen_logo" to Assets.xcassets it will be used automatically.
+// Otherwise a brand-styled text badge is shown.
+struct UGreenCompatibilityBadge: View {
+    private static let ugreenGreen = Color(hex: "#00B388")
+    private let hasLogo = UIImage(named: "ugreen_logo") != nil
+
+    var body: some View {
+        HStack(spacing: 8) {
+            // UGreen logo or fallback wordmark
+            if hasLogo {
+                Image("ugreen_logo")
+                    .resizable()
+                    .scaledToFit()
+                    .frame(height: 14)
+            } else {
+                HStack(spacing: 4) {
+                    // Brand dot
+                    Circle()
+                        .fill(Self.ugreenGreen)
+                        .frame(width: 6, height: 6)
+                    Text("UGreen NAS")
+                        .font(.system(size: 11, weight: .semibold))
+                        .foregroundStyle(Self.ugreenGreen)
+                }
+            }
+
+            // Separator
+            Rectangle()
+                .fill(AppTheme.inkQuaternary)
+                .frame(width: 0.5, height: 11)
+
+            // Protocol hint
+            Text("SMB · SFTP")
+                .font(.system(size: 11, weight: .regular))
+                .foregroundStyle(AppTheme.inkTertiary)
+        }
+        .padding(.horizontal, 12)
+        .padding(.vertical, 6)
+        .background(AppTheme.surfaceSunken)
+        .clipShape(Capsule(style: .continuous))
+    }
+}