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/ButtonStyles.swift

@@ -1,6 +1,6 @@
 import SwiftUI
 
-// MARK: — Primary (black fill)
+// MARK: — Primary (ink fill)
 struct PrimaryButtonStyle: ButtonStyle {
     var color: Color = AppTheme.ink
     var height: CGFloat = 50
@@ -8,7 +8,7 @@ struct PrimaryButtonStyle: ButtonStyle {
     func makeBody(configuration: Configuration) -> some View {
         configuration.label
             .font(.system(size: 15, weight: .medium))
-            .foregroundColor(.white)
+            .foregroundStyle(AppTheme.inkInverse)
             .frame(maxWidth: .infinity)
             .frame(height: height)
             .background(color)
@@ -25,12 +25,12 @@ struct GhostButtonStyle: ButtonStyle {
     func makeBody(configuration: Configuration) -> some View {
         configuration.label
             .font(.system(size: 15, weight: .medium))
-            .foregroundColor(AppTheme.ink)
+            .foregroundStyle(AppTheme.ink)
             .frame(maxWidth: .infinity)
             .frame(height: height)
             .overlay(
                 RoundedRectangle(cornerRadius: AppTheme.radius, style: .continuous)
-                    .stroke(AppTheme.cardBorderColor, lineWidth: 1)
+                    .stroke(AppTheme.ink.opacity(0.25), lineWidth: 1)
             )
             .scaleEffect(configuration.isPressed ? 0.97 : 1)
             .animation(.spring(response: 0.25, dampingFraction: 0.7), value: configuration.isPressed)
@@ -52,7 +52,7 @@ struct PillButtonStyle: ButtonStyle {
     func makeBody(configuration: Configuration) -> some View {
         configuration.label
             .font(.system(size: 13, weight: .medium))
-            .foregroundColor(.white)
+            .foregroundStyle(AppTheme.inkInverse)
             .padding(.horizontal, 14)
             .padding(.vertical, 7)
             .background(color)