refactor: split Scenes out of MainViewModel — Commit 3/12 (tag refactor-commit-3)

Pure member movement into MainViewModel.License.cs (zero behavior change):
Polar license state (LicenseKey/LicenseMessage/IsLicenseValidating/
IsLicenseEntryOpen/IsHubVisible/IsPremium + OfflineGracePeriod),
ValidateLicenseAtStartupAsync, ActivateLicenseAsync. docs in same commit:
ViewModels/index.md split table (License ✔).

ViewModels/MainViewModel.Account.cs

@@ -0,0 +1,132 @@
+using ytLive.Helpers;
+using ytLive.Models;
+using ytLive.Services;
+
+namespace ytLive.ViewModels;
+
+public partial class MainViewModel
+{
+    private bool _isConnected;
+    private string _accountAvatarUrl = string.Empty;
+    private string _accountDisplayName = string.Empty;
+
+    public bool IsConnected
+    {
+        get => _isConnected;
+        set
+        {
+            if (SetProperty(ref _isConnected, value))
+            {
+                // ON-AIR requires a sign-in; dropping the session turns the pill
+                // off so the state can never offer a stream without an account.
+                if (!value) OnAirPillOn = false;
+                OnPropertyChanged(nameof(CanToggleOnAir));
+                OnPropertyChanged(nameof(ShowPrimaryStartButton));
+                OnPropertyChanged(nameof(AccountStatusLightToolTip));
+            }
+        }
+    }
+
+    /// <summary>The connected YouTube account's avatar + name — shown in the top
+    /// bar so the creator always sees WHICH account is about to go live.</summary>
+    public string AccountAvatarUrl
+    {
+        get => _accountAvatarUrl;
+        private set => SetProperty(ref _accountAvatarUrl, value);
+    }
+
+    public string AccountDisplayName
+    {
+        get => _accountDisplayName;
+        private set => SetProperty(ref _accountDisplayName, value);
+    }
+
+    /// <summary>Tooltip for the account status light explaining the color.</summary>
+    public string AccountStatusLightToolTip =>
+        IsLive ? "Live on YouTube — the top bar is red to show the stream is on the air."
+        : IsConnected ? "You're signed in to YouTube. The light is green; ON-AIR is available."
+        : "Signed out — the light is red and the ON-AIR pill is greyed out. You can still record locally.";
+
+    // Restores the DPAPI-saved OAuth session so sign-in survives restarts.
+    // Best-effort: refresh a near-expiry access token; a session that can no
+    // longer refresh is discarded and the user signs in again.
+    private async Task LoadSavedSessionAsync()
+    {
+        try
+        {
+            var saved = TokenStore.Load();
+            if (saved == null) return;
+
+            _youtubeAuth.SetSession(saved);
+            if (saved.TokenExpiry <= DateTime.UtcNow.AddMinutes(5))
+            {
+                var refreshed = await Task.Run(() => _youtubeAuth.RefreshToken());
+                if (!refreshed)
+                {
+                    TokenStore.Clear();
+                    AppLog.Write("Saved session could not be refreshed; signed out");
+                    _notifications.Info("Signed out of YouTube",
+                        "The saved session expired — sign in again when you next go live.");
+                    return;
+                }
+            }
+
+            IsConnected = true;
+            SyncConnectedAccount();
+        }
+        catch (Exception ex)
+        {
+            AppLog.Write($"LoadSavedSessionAsync failed: {ex}");
+        }
+    }
+
+    private void SyncConnectedAccount()
+    {
+        var channel = _youtubeAuth.CurrentChannel;
+        AccountAvatarUrl = channel?.ProfileImageUrl ?? string.Empty;
+        AccountDisplayName = channel?.DisplayName ?? string.Empty;
+    }
+
+    // Runs the OAuth flow (browser + loopback callback) on a background thread.
+    // The resulting channel is returned to the caller and persisted via the
+    // auth service's sessionChanged hook.
+    private async Task<YouTubeChannel?> SignInAsync()
+    {
+        try
+        {
+            var channel = await Task.Run(() => _youtubeAuth.AuthenticateAsync());
+            if (channel == null)
+            {
+                _notifications.Warning("Sign-in was unsuccessful", "Please try again.");
+                return null;
+            }
+
+            IsConnected = true;
+            SyncConnectedAccount();
+            return channel;
+        }
+        catch (Exception ex)
+        {
+            _notifications.Error("Sign-in failed", ex.Message);
+            return null;
+        }
+    }
+
+    /// <summary>Signs out of YouTube (the delete-the-YouTube-slot action in the dialog).</summary>
+    private async Task SignOutYouTubeAsync()
+    {
+        _youtubeAuth.ClearSession();
+        TokenStore.Clear();
+        IsConnected = false;
+        SyncConnectedAccount();
+        NotifySocialsChanged();
+        AppLog.Write("Socials: signed out of YouTube");
+        await Task.CompletedTask;
+    }
+
+    private async Task ChangeAccountAsync()
+    {
+        await SignOutYouTubeAsync();
+        await SignInAsync();
+    }
+}

ViewModels/MainViewModel.License.cs

@@ -0,0 +1,162 @@
+using ytLive.Helpers;
+using ytLive.Services;
+
+namespace ytLive.ViewModels;
+
+public partial class MainViewModel
+{
+    // TASK 10 — Polar license validation
+    private string _licenseKey = string.Empty;
+    private string _licenseMessage = string.Empty;
+    private bool _isLicenseValidating;
+    private bool _isLicenseEntryOpen;
+    private static readonly TimeSpan OfflineGracePeriod = TimeSpan.FromDays(14);
+
+    /// <summary>True when the user holds a valid LlamaCasty license (Polar). When
+    /// false, the branding flash runs on every live stream.</summary>
+    private bool _isPremium;
+    public bool IsPremium
+    {
+        get => _isPremium;
+        private set
+        {
+            if (!SetProperty(ref _isPremium, value)) return;
+            // Flip the branding flash when premium state changes.
+            BrandFlashEnabled = !value;
+        }
+    }
+
+    // TASK 10 — license key entry
+    public string LicenseKey
+    {
+        get => _licenseKey;
+        set => SetProperty(ref _licenseKey, value);
+    }
+
+    public string LicenseMessage
+    {
+        get => _licenseMessage;
+        private set => SetProperty(ref _licenseMessage, value);
+    }
+
+    public bool IsLicenseValidating
+    {
+        get => _isLicenseValidating;
+        private set => SetProperty(ref _isLicenseValidating, value);
+    }
+
+    public bool IsLicenseEntryOpen
+    {
+        get => _isLicenseEntryOpen;
+        set
+        {
+            if (SetProperty(ref _isLicenseEntryOpen, value))
+                OnPropertyChanged(nameof(IsHubVisible));
+        }
+    }
+
+    /// <summary>The About hub is visible only when neither the licenses panel
+    /// nor the license entry panel is open.</summary>
+    public bool IsHubVisible => !IsLicensesOpen && !IsLicenseEntryOpen;
+
+    // ─── TASK 10 — Polar license validation ───
+
+    /// <summary>At startup, load the cached license state and re-validate online
+    /// if a key exists. If offline and within the 14-day grace period, the cached
+    /// premium state is trusted. If the grace period is exceeded, premium lapses.</summary>
+    private async Task ValidateLicenseAtStartupAsync()
+    {
+        var savedKey = _layoutStore.LoadLicenseKey();
+        if (string.IsNullOrWhiteSpace(savedKey))
+        {
+            IsPremium = false;
+            return;
+        }
+
+        LicenseKey = savedKey;
+        var validatedAt = _layoutStore.LoadLicenseValidatedAt();
+        var cachedPremium = _layoutStore.LoadIsPremium();
+
+        // If the last validation was within the grace period, trust the cache
+        // while we attempt an online re-validation in the background.
+        if (validatedAt.HasValue && DateTime.UtcNow - validatedAt.Value < OfflineGracePeriod)
+        {
+            IsPremium = cachedPremium;
+        }
+
+        // Try an online check — if it succeeds, it overrides the cache.
+        try
+        {
+            var service = new PolarLicenseService();
+            var result = await service.ValidateAsync(savedKey);
+            if (result.IsValid)
+            {
+                IsPremium = true;
+                _layoutStore.SaveIsPremium(true);
+                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
+            }
+            else
+            {
+                // Key revoked or expired — clear premium.
+                IsPremium = false;
+                _layoutStore.SaveIsPremium(false);
+                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
+                AppLog.Write($"License validation failed: {result.Error}");
+                _notifications.Warning("Premium is no longer active",
+                    $"{result.Error} — watermark branding returns until the license is renewed.");
+            }
+        }
+        catch (Exception ex)
+        {
+            // Offline or network error — keep the cached state, log it.
+            AppLog.Write($"License re-validation skipped (offline?): {ex.Message}");
+            if (!validatedAt.HasValue || DateTime.UtcNow - validatedAt.Value >= OfflineGracePeriod)
+            {
+                IsPremium = false;
+                _layoutStore.SaveIsPremium(false);
+            }
+        }
+    }
+
+    /// <summary>Called from the Activate button in the About overlay. Validates
+    /// the entered key, persists it, and flips premium state.</summary>
+    private async Task ActivateLicenseAsync()
+    {
+        if (string.IsNullOrWhiteSpace(LicenseKey)) return;
+
+        IsLicenseValidating = true;
+        LicenseMessage = "Validating\u2026";
+
+        try
+        {
+            var service = new PolarLicenseService();
+            var result = await service.ValidateAsync(LicenseKey);
+            if (result.IsValid)
+            {
+                IsPremium = true;
+                _layoutStore.SaveLicenseKey(LicenseKey.Trim());
+                _layoutStore.SaveIsPremium(true);
+                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
+                LicenseMessage = "Premium activated! The watermark has been removed.";
+                AppLog.Write("License activated successfully");
+            }
+            else
+            {
+                IsPremium = false;
+                _layoutStore.SaveLicenseKey(null);
+                _layoutStore.SaveIsPremium(false);
+                LicenseMessage = result.Error ?? "Invalid license key.";
+                AppLog.Write($"License activation failed: {result.Error}");
+            }
+        }
+        catch (Exception ex)
+        {
+            LicenseMessage = $"Activation error: {ex.Message}";
+            AppLog.Write($"License activation error: {ex}");
+        }
+        finally
+        {
+            IsLicenseValidating = false;
+        }
+    }
+}

ViewModels/MainViewModel.Scenes.cs

@@ -0,0 +1,273 @@
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.ComponentModel;
+using System.Windows;
+using ytLive;
+using ytLive.Models;
+using ytLive.Services;
+
+namespace ytLive.ViewModels;
+
+public partial class MainViewModel
+{
+    private Scene? _stagedScene;
+    private Scene? _liveScene;
+
+    // TASK 20 step 2 — hotkey bindings (custom chord per action)
+    private Dictionary<HotkeyId, HotkeyChord> _hotkeyBindings = new();
+
+    public ObservableCollection<Scene> Scenes { get; } = new();
+
+    public Scene? StagedScene
+    {
+        get => _stagedScene;
+        set
+        {
+            if (value != null && value.IsHidden) return;
+            if (SetProperty(ref _stagedScene, value))
+            {
+                // Update IsStaged flags for thumbnail glow
+                foreach (var s in Scenes)
+                    s.IsStaged = s == value;
+
+                SelectedElement = null;
+                if (value != null)
+                {
+                    var background = EnsureBackground(value);
+                    if (background != null)
+                        StampDefaultBackgroundAsset(background, value.Name);
+                }
+                OnPropertyChanged(nameof(ShowChatInactiveMessage));
+                OnPropertyChanged(nameof(ShowEmptySceneHint));
+                OnPropertyChanged(nameof(ShowPreviewPlaceholder));
+                OnPropertyChanged(nameof(ShowSourcesEmptyHint));
+                OnPropertyChanged(nameof(CanChangeBackground));
+                OnPropertyChanged(nameof(CanAddWebcam));
+                OnPropertyChanged(nameof(CanAddYouTubeChat));
+                OnPropertyChanged(nameof(CanShowWebcamInStagedScene));
+                OnPropertyChanged(nameof(IsCountdownAvailable));
+                UpdateActiveBackground();
+                UpdateBackgroundImage();
+                RefreshSnapshotsAsync();
+            }
+        }
+    }
+
+    /// <summary>The scene the encoder outputs. Set on Go Live (StagedScene → LiveScene)
+    /// or on transition completion. FramePump reads this every tick.</summary>
+    public Scene? LiveScene
+    {
+        get => _liveScene;
+        set
+        {
+            if (SetProperty(ref _liveScene, value))
+            {
+                foreach (var s in Scenes)
+                    s.IsLive = s == value;
+            }
+        }
+    }
+
+    /// <summary>True when offline — edit mode is available. When live/recording,
+    /// all edit operations are locked out (gun safety).</summary>
+    public bool IsEditMode => StreamStatus == StreamStatus.Offline && !IsRecording;
+
+    // ─── Transitions (TASK 19/23) ───
+
+    public TransitionType SelectedTransitionType
+    {
+        get => _selectedTransitionType;
+        set => SetProperty(ref _selectedTransitionType, value);
+    }
+    private TransitionType _selectedTransitionType = TransitionType.Fade;
+
+    public double TransitionDurationMs
+    {
+        get => _transitionDurationMs;
+        set => SetProperty(ref _transitionDurationMs, value);
+    }
+    private double _transitionDurationMs = 300;
+
+    /// <summary>
+    /// Called when a scene thumbnail is clicked. If live, triggers a transition from
+    /// LiveScene to the selected StagedScene. Always sets StagedScene first.
+    /// </summary>
+    public void TransitionToScene(Scene scene)
+    {
+        if (scene.IsHidden || scene == StagedScene) return;
+        StagedScene = scene;
+        if (IsLive)
+            _transition.Start(SelectedTransitionType, TransitionDurationMs, null);
+    }
+
+    /// <summary>
+    /// Apply the current transition type to the next StagedScene change while live.
+    /// Called from XAML when user picks a transition from the dropdown.
+    /// </summary>
+    public void ApplyTransitionToLive()
+    {
+        if (IsLive)
+            _transition.Start(SelectedTransitionType, TransitionDurationMs, null);
+    }
+
+    // ─── Global hotkeys (TASK 20) — dispatch a registered hotkey to its action ───
+
+    /// <summary>
+    /// Callback set by MainWindow so the VM can trigger hotkey re-registration
+    /// after the user saves custom bindings from the config dialog.
+    /// </summary>
+    public Action<Dictionary<HotkeyId, HotkeyChord>>? HotkeyBindingsChanged { get; set; }
+
+    /// <summary>The current hotkey bindings (loaded from DB, updated on dialog save).</summary>
+    public Dictionary<HotkeyId, HotkeyChord> CurrentHotkeyBindings => _hotkeyBindings;
+
+    public void HandleHotkey(Services.HotkeyId id)
+    {
+        switch (id)
+        {
+            case Services.HotkeyId.SceneStarting: TransitionToCanonical(SceneCatalog.Starting); break;
+            case Services.HotkeyId.SceneLive: TransitionToCanonical(SceneCatalog.Live); break;
+            case Services.HotkeyId.SceneBrb: TransitionToCanonical(SceneCatalog.Brb); break;
+            case Services.HotkeyId.SceneChat: TransitionToCanonical(SceneCatalog.Chat); break;
+            case Services.HotkeyId.SceneEnding: TransitionToCanonical(SceneCatalog.Ending); break;
+            case Services.HotkeyId.StartStopStream:
+                if (IsLive || IsRecording)
+                {
+                    if (EndStreamCommand.CanExecute(null)) EndStreamCommand.Execute(null);
+                }
+                else if (StartStreamCommand.CanExecute(null))
+                {
+                    StartStreamCommand.Execute(null);
+                }
+                break;
+            case Services.HotkeyId.ToggleMicMute: ToggleMicMuteCommand.Execute(null); break;
+            case Services.HotkeyId.ToggleGameMute: ToggleGameMuteCommand.Execute(null); break;
+            case Services.HotkeyId.TraxPlayPause: TraxLeftClick(); break;
+        }
+    }
+
+    private void TransitionToCanonical(string name)
+    {
+        var scene = Scenes.FirstOrDefault(s => SceneCatalog.Is(s.Name, name));
+        if (scene != null) TransitionToScene(scene);
+    }
+
+    private void OpenHotkeyConfig()
+    {
+        var vm = new HotkeyConfigViewModel(_layoutStore);
+        var dialog = new HotkeyConfigDialog(vm) { Owner = Application.Current.MainWindow };
+        if (dialog.ShowDialog() == true)
+        {
+            // Reload bindings from DB (the dialog already saved them).
+            _hotkeyBindings = _layoutStore.LoadHotkeyBindings();
+            HotkeyBindingsChanged?.Invoke(_hotkeyBindings);
+            RefreshHotkeyLabels();
+        }
+    }
+
+    private void RefreshHotkeyLabels()
+    {
+        foreach (var scene in Scenes)
+        {
+            if (SceneCatalog.SceneHotkeys.TryGetValue(scene.Name, out var hid)
+                && _hotkeyBindings.TryGetValue(hid, out var chord))
+                scene.HotkeyLabel = chord.ToDisplayString();
+            else if (SceneCatalog.SceneHotkeys.TryGetValue(scene.Name, out var defId)
+                     && GlobalHotkeyManager.Defaults.TryGetValue(defId, out var defChord))
+                scene.HotkeyLabel = defChord.ToDisplayString();
+            else
+                scene.HotkeyLabel = string.Empty;
+        }
+    }
+
+    public bool ShowEmptySceneHint => StagedScene != null && StagedScene.Elements.Count == 0;
+    public bool ShowSourcesEmptyHint => StagedScene == null || StagedScene.Elements.Count == 0;
+
+    public bool IsCountdownAvailable => StagedScene != null
+        && (SceneCatalog.Is(StagedScene.Name, "Starting") || SceneCatalog.Is(StagedScene.Name, "BRB"));
+
+    /// <summary>The canonical scenes (SceneCatalog) not present right now — what the
+    /// "+" button may re-add. Work with less, never more.</summary>
+    public IEnumerable<string> MissingScenes
+        => SceneCatalog.All.Where(canonical => Scenes.All(s => !SceneCatalog.Is(s.Name, canonical)));
+
+    /// <summary>Only show the "+" button when one of the five canonical scenes is missing.</summary>
+    public bool ShowAddScene => MissingScenes.Any();
+
+    /// <summary>"Change Capture…"/"Refresh Capture" apply to the active scene's background.</summary>
+    // Capture controls (Show Desktop / monitor pick / refresh) exist only on
+    // the Live screen's Background. Static-art screens never expose them.
+    public bool CanChangeBackground =>
+        StagedScene != null && SceneCatalog.Is(StagedScene.Name, SceneCatalog.Live);
+
+    // ─── Auto-save wiring ───
+    private void OnScenesChanged(object? sender, NotifyCollectionChangedEventArgs e)
+    {
+        if (e.NewItems != null)
+            foreach (Scene scene in e.NewItems)
+                WireScene(scene);
+        if (e.OldItems != null)
+            foreach (Scene scene in e.OldItems)
+                UnwireScene(scene);
+        OnPropertyChanged(nameof(MissingScenes));
+        OnPropertyChanged(nameof(ShowAddScene));
+        ScheduleSave();
+    }
+
+    private void WireScene(Scene scene)
+    {
+        scene.PropertyChanged += OnScenePropertyChanged;
+        scene.Elements.CollectionChanged += OnElementsChanged;
+    }
+
+    private void UnwireScene(Scene scene)
+    {
+        scene.PropertyChanged -= OnScenePropertyChanged;
+        scene.Elements.CollectionChanged -= OnElementsChanged;
+    }
+
+    private void OnScenePropertyChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        // A rename can drop a canonical scene in/out of MissingScenes.
+        OnPropertyChanged(nameof(MissingScenes));
+        OnPropertyChanged(nameof(ShowAddScene));
+        ScheduleSave();
+    }
+
+    private void OnElementsChanged(object? sender, NotifyCollectionChangedEventArgs e)
+    {
+        if (e.NewItems != null)
+            foreach (SceneElement element in e.NewItems)
+                element.PropertyChanged += OnElementPropertyChanged;
+        if (e.OldItems != null)
+            foreach (SceneElement element in e.OldItems)
+                element.PropertyChanged -= OnElementPropertyChanged;
+        OnPropertyChanged(nameof(CanAddWebcam));
+        OnPropertyChanged(nameof(CanAddYouTubeChat));
+        ScheduleSave();
+    }
+
+    private void OnElementPropertyChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        if (sender is WebcamSceneConfig && e.PropertyName == nameof(SceneElement.IsVisible))
+            OnPropertyChanged(nameof(CanShowWebcamInStagedScene));
+        ScheduleSave();
+    }
+
+    // Adds a canonical scene by name — only when it's actually missing. The
+    // background flag follows the policy (Live yes, everyone else no).
+    private void AddScene(string name)
+    {
+        if (!SceneCatalog.IsCanonical(name)) return;
+        if (Scenes.Any(s => SceneCatalog.Is(s.Name, name))) return;
+        var scene = new Scene
+        {
+            Name = name.Trim(),
+            IsChatScene = SceneCatalog.IsChat(name),
+            HasBackground = SceneCatalog.HasBackground(name),
+        };
+        EnsureBackground(scene);
+        Scenes.Add(scene);
+        StagedScene = scene;
+    }
+}

ViewModels/MainViewModel.cs

@@ -31,13 +31,8 @@ public partial class MainViewModel : ViewModelBase
     private readonly DispatcherTimer _gameVolumeFlashTimer;
     private readonly DispatcherTimer _healthPollTimer;
 
-    private Scene? _stagedScene;
-    private Scene? _liveScene;
     private SceneElement? _selectedElement;
     private ImageSource? _activeBackgroundImage;
-    private bool _isConnected;
-    private string _accountAvatarUrl = string.Empty;
-    private string _accountDisplayName = string.Empty;
     private double _audioLevel;
     private bool _volumeAdjusting;
     private bool _volumeFlash;
@@ -173,16 +168,6 @@ public partial class MainViewModel : ViewModelBase
     private bool _brandFlashEnabled = true;
     private bool _brandFlashActive;
 
-    // TASK 20 step 2 — hotkey bindings (custom chord per action)
-    private Dictionary<HotkeyId, HotkeyChord> _hotkeyBindings = new();
-
-    // TASK 10 — Polar license validation
-    private string _licenseKey = string.Empty;
-    private string _licenseMessage = string.Empty;
-    private bool _isLicenseValidating;
-    private bool _isLicenseEntryOpen;
-    private static readonly TimeSpan OfflineGracePeriod = TimeSpan.FromDays(14);
-
     private const string SupportEmail = "gramps@llamachile.shop";
     // The creator-hub link targets (About overlay) — public so the hub's
     // integration test can assert they point at real destinations.
@@ -200,64 +185,9 @@ public partial class MainViewModel : ViewModelBase
     /// shipped THIRD-PARTY-NOTICES.txt (never opens the OS viewer).</summary>
     public string LicensesText { get; private set; } = string.Empty;
 
-    public ObservableCollection<Scene> Scenes { get; } = new();
     public ObservableCollection<ChatMessage> ChatMessages { get; } = new();
     public ObservableCollection<DisplayInfo> Displays { get; } = new();
 
-    public Scene? StagedScene
-    {
-        get => _stagedScene;
-        set
-        {
-            if (value != null && value.IsHidden) return;
-            if (SetProperty(ref _stagedScene, value))
-            {
-                // Update IsStaged flags for thumbnail glow
-                foreach (var s in Scenes)
-                    s.IsStaged = s == value;
-
-                SelectedElement = null;
-                if (value != null)
-                {
-                    var background = EnsureBackground(value);
-                    if (background != null)
-                        StampDefaultBackgroundAsset(background, value.Name);
-                }
-                OnPropertyChanged(nameof(ShowChatInactiveMessage));
-                OnPropertyChanged(nameof(ShowEmptySceneHint));
-                OnPropertyChanged(nameof(ShowPreviewPlaceholder));
-                OnPropertyChanged(nameof(ShowSourcesEmptyHint));
-                OnPropertyChanged(nameof(CanChangeBackground));
-                OnPropertyChanged(nameof(CanAddWebcam));
-                OnPropertyChanged(nameof(CanAddYouTubeChat));
-                OnPropertyChanged(nameof(CanShowWebcamInStagedScene));
-                OnPropertyChanged(nameof(IsCountdownAvailable));
-                UpdateActiveBackground();
-                UpdateBackgroundImage();
-                RefreshSnapshotsAsync();
-            }
-        }
-    }
-
-    /// <summary>The scene the encoder outputs. Set on Go Live (StagedScene → LiveScene)
-    /// or on transition completion. FramePump reads this every tick.</summary>
-    public Scene? LiveScene
-    {
-        get => _liveScene;
-        set
-        {
-            if (SetProperty(ref _liveScene, value))
-            {
-                foreach (var s in Scenes)
-                    s.IsLive = s == value;
-            }
-        }
-    }
-
-    /// <summary>True when offline — edit mode is available. When live/recording,
-    /// all edit operations are locked out (gun safety).</summary>
-    public bool IsEditMode => StreamStatus == StreamStatus.Offline && !IsRecording;
-
     public ImageSource? ActiveBackgroundImage
     {
         get => _activeBackgroundImage;
@@ -330,114 +260,6 @@ public partial class MainViewModel : ViewModelBase
         => StagedScene != null
            && !Scenes.Any(s => s.Elements.OfType<Source>().Any(e => e.Type == SourceType.ChatBox));
 
-    // ─── Transitions (TASK 19/23) ───
-
-    public TransitionType SelectedTransitionType
-    {
-        get => _selectedTransitionType;
-        set => SetProperty(ref _selectedTransitionType, value);
-    }
-    private TransitionType _selectedTransitionType = TransitionType.Fade;
-
-    public double TransitionDurationMs
-    {
-        get => _transitionDurationMs;
-        set => SetProperty(ref _transitionDurationMs, value);
-    }
-    private double _transitionDurationMs = 300;
-
-    /// <summary>
-    /// Called when a scene thumbnail is clicked. If live, triggers a transition from
-    /// LiveScene to the selected StagedScene. Always sets StagedScene first.
-    /// </summary>
-    public void TransitionToScene(Scene scene)
-    {
-        if (scene.IsHidden || scene == StagedScene) return;
-        StagedScene = scene;
-        if (IsLive)
-            _transition.Start(SelectedTransitionType, TransitionDurationMs, null);
-    }
-
-    /// <summary>
-    /// Apply the current transition type to the next StagedScene change while live.
-    /// Called from XAML when user picks a transition from the dropdown.
-    /// </summary>
-    public void ApplyTransitionToLive()
-    {
-        if (IsLive)
-            _transition.Start(SelectedTransitionType, TransitionDurationMs, null);
-    }
-
-    // ─── Global hotkeys (TASK 20) — dispatch a registered hotkey to its action ───
-
-    /// <summary>
-    /// Callback set by MainWindow so the VM can trigger hotkey re-registration
-    /// after the user saves custom bindings from the config dialog.
-    /// </summary>
-    public Action<Dictionary<HotkeyId, HotkeyChord>>? HotkeyBindingsChanged { get; set; }
-
-    /// <summary>The current hotkey bindings (loaded from DB, updated on dialog save).</summary>
-    public Dictionary<HotkeyId, HotkeyChord> CurrentHotkeyBindings => _hotkeyBindings;
-
-    public void HandleHotkey(Services.HotkeyId id)
-    {
-        switch (id)
-        {
-            case Services.HotkeyId.SceneStarting: TransitionToCanonical(SceneCatalog.Starting); break;
-            case Services.HotkeyId.SceneLive: TransitionToCanonical(SceneCatalog.Live); break;
-            case Services.HotkeyId.SceneBrb: TransitionToCanonical(SceneCatalog.Brb); break;
-            case Services.HotkeyId.SceneChat: TransitionToCanonical(SceneCatalog.Chat); break;
-            case Services.HotkeyId.SceneEnding: TransitionToCanonical(SceneCatalog.Ending); break;
-            case Services.HotkeyId.StartStopStream:
-                if (IsLive || IsRecording)
-                {
-                    if (EndStreamCommand.CanExecute(null)) EndStreamCommand.Execute(null);
-                }
-                else if (StartStreamCommand.CanExecute(null))
-                {
-                    StartStreamCommand.Execute(null);
-                }
-                break;
-            case Services.HotkeyId.ToggleMicMute: ToggleMicMuteCommand.Execute(null); break;
-            case Services.HotkeyId.ToggleGameMute: ToggleGameMuteCommand.Execute(null); break;
-            case Services.HotkeyId.TraxPlayPause: TraxLeftClick(); break;
-        }
-    }
-
-    private void TransitionToCanonical(string name)
-    {
-        var scene = Scenes.FirstOrDefault(s => SceneCatalog.Is(s.Name, name));
-        if (scene != null) TransitionToScene(scene);
-    }
-
-    private void OpenHotkeyConfig()
-    {
-        var vm = new HotkeyConfigViewModel(_layoutStore);
-        var dialog = new HotkeyConfigDialog(vm) { Owner = Application.Current.MainWindow };
-        if (dialog.ShowDialog() == true)
-        {
-            // Reload bindings from DB (the dialog already saved them).
-            _hotkeyBindings = _layoutStore.LoadHotkeyBindings();
-            HotkeyBindingsChanged?.Invoke(_hotkeyBindings);
-            RefreshHotkeyLabels();
-        }
-    }
-
-    private void RefreshHotkeyLabels()
-    {
-        foreach (var scene in Scenes)
-        {
-            if (SceneCatalog.SceneHotkeys.TryGetValue(scene.Name, out var hid)
-                && _hotkeyBindings.TryGetValue(hid, out var chord))
-                scene.HotkeyLabel = chord.ToDisplayString();
-            else if (SceneCatalog.SceneHotkeys.TryGetValue(scene.Name, out var defId)
-                     && GlobalHotkeyManager.Defaults.TryGetValue(defId, out var defChord))
-                scene.HotkeyLabel = defChord.ToDisplayString();
-            else
-                scene.HotkeyLabel = string.Empty;
-        }
-    }
-
     /// <summary>
     /// Right-click-on-preview → "Show Webcam": offered when the active scene has no
     /// webcam config (add one) or hides it (unhide — keeps the config row).
@@ -470,20 +292,6 @@ public partial class MainViewModel : ViewModelBase
     /// <summary>The global socials config (entries + bar settings), or null.</summary>
     public SocialsConfig? Socials => _socials;
 
-    /// <summary>True when the user holds a valid LlamaCasty license (Polar). When
-    /// false, the branding flash runs on every live stream.</summary>
-    private bool _isPremium;
-    public bool IsPremium
-    {
-        get => _isPremium;
-        private set
-        {
-            if (!SetProperty(ref _isPremium, value)) return;
-            // Flip the branding flash when premium state changes.
-            BrandFlashEnabled = !value;
-        }
-    }
-
     /// <summary>Canvas.Top for the social bar: 0 = top, 1040 = bottom (40px from the 1080 edge).</summary>
     public double SocialBarTop => _socials?.BarPosition == SocialBarPosition.Top ? 0 : 1040;
 
@@ -535,37 +343,6 @@ public partial class MainViewModel : ViewModelBase
         }
     }
 
-    public bool IsConnected
-    {
-        get => _isConnected;
-        set
-        {
-            if (SetProperty(ref _isConnected, value))
-            {
-                // ON-AIR requires a sign-in; dropping the session turns the pill
-                // off so the state can never offer a stream without an account.
-                if (!value) OnAirPillOn = false;
-                OnPropertyChanged(nameof(CanToggleOnAir));
-                OnPropertyChanged(nameof(ShowPrimaryStartButton));
-                OnPropertyChanged(nameof(AccountStatusLightToolTip));
-            }
-        }
-    }
-
-    /// <summary>The connected YouTube account's avatar + name — shown in the top
-    /// bar so the creator always sees WHICH account is about to go live.</summary>
-    public string AccountAvatarUrl
-    {
-        get => _accountAvatarUrl;
-        private set => SetProperty(ref _accountAvatarUrl, value);
-    }
-
-    public string AccountDisplayName
-    {
-        get => _accountDisplayName;
-        private set => SetProperty(ref _accountDisplayName, value);
-    }
-
     // ─── Audio: the mic bar (meter + volume + mute + status dot) is always
     // ─── visible; the game bar (meter + volume + mute) appears only while a
     // ─── full-screen game is producing sound. Both meters preview live. ───
@@ -1062,32 +839,8 @@ public partial class MainViewModel : ViewModelBase
 
     public bool ShowLogInButton => !IsConnected && IsOffline && !IsRecording;
 
-    /// <summary>Tooltip for the account status light explaining the color.</summary>
-    public string AccountStatusLightToolTip =>
-        IsLive ? "Live on YouTube — the top bar is red to show the stream is on the air."
-        : IsConnected ? "You're signed in to YouTube. The light is green; ON-AIR is available."
-        : "Signed out — the light is red and the ON-AIR pill is greyed out. You can still record locally.";
     public bool ShowChatInactiveMessage => !IsLive;
-    public bool ShowEmptySceneHint => StagedScene != null && StagedScene.Elements.Count == 0;
     public bool ShowPreviewPlaceholder => !ShowEmptySceneHint && ActiveBackgroundImage == null && BackgroundImage == null;
-    public bool ShowSourcesEmptyHint => StagedScene == null || StagedScene.Elements.Count == 0;
-
-    public bool IsCountdownAvailable => StagedScene != null
-        && (SceneCatalog.Is(StagedScene.Name, "Starting") || SceneCatalog.Is(StagedScene.Name, "BRB"));
-
-    /// <summary>The canonical scenes (SceneCatalog) not present right now — what the
-    /// "+" button may re-add. Work with less, never more.</summary>
-    public IEnumerable<string> MissingScenes
-        => SceneCatalog.All.Where(canonical => Scenes.All(s => !SceneCatalog.Is(s.Name, canonical)));
-
-    /// <summary>Only show the "+" button when one of the five canonical scenes is missing.</summary>
-    public bool ShowAddScene => MissingScenes.Any();
-
-    /// <summary>"Change Capture…"/"Refresh Capture" apply to the active scene's background.</summary>
-    // Capture controls (Show Desktop / monitor pick / refresh) exist only on
-    // the Live screen's Background. Static-art screens never expose them.
-    public bool CanChangeBackground =>
-        StagedScene != null && SceneCatalog.Is(StagedScene.Name, SceneCatalog.Live);
 
     // Paid unlock flips this off (see ai.md "Monetization"). When disabled the
     // cadence timer is stopped and any active flash is hidden immediately.
@@ -1550,39 +1303,6 @@ public partial class MainViewModel : ViewModelBase
         set => SetProperty(ref _featureRequestEmail, value);
     }
 
-    // TASK 10 — license key entry
-    public string LicenseKey
-    {
-        get => _licenseKey;
-        set => SetProperty(ref _licenseKey, value);
-    }
-
-    public string LicenseMessage
-    {
-        get => _licenseMessage;
-        private set => SetProperty(ref _licenseMessage, value);
-    }
-
-    public bool IsLicenseValidating
-    {
-        get => _isLicenseValidating;
-        private set => SetProperty(ref _isLicenseValidating, value);
-    }
-
-    public bool IsLicenseEntryOpen
-    {
-        get => _isLicenseEntryOpen;
-        set
-        {
-            if (SetProperty(ref _isLicenseEntryOpen, value))
-                OnPropertyChanged(nameof(IsHubVisible));
-        }
-    }
-
-    /// <summary>The About hub is visible only when neither the licenses panel
-    /// nor the license entry panel is open.</summary>
-    public bool IsHubVisible => !IsLicensesOpen && !IsLicenseEntryOpen;
-
     // Commands
     public ICommand AddSceneCommand { get; }
     public ICommand AddSourceCommand { get; }
@@ -1789,147 +1509,6 @@ public partial class MainViewModel : ViewModelBase
         AppLog.Write("MainViewModel ctor end");
     }
 
-    // Restores the DPAPI-saved OAuth session so sign-in survives restarts.
-    // Best-effort: refresh a near-expiry access token; a session that can no
-    // longer refresh is discarded and the user signs in again.
-    private async Task LoadSavedSessionAsync()
-    {
-        try
-        {
-            var saved = TokenStore.Load();
-            if (saved == null) return;
-
-            _youtubeAuth.SetSession(saved);
-            if (saved.TokenExpiry <= DateTime.UtcNow.AddMinutes(5))
-            {
-                var refreshed = await Task.Run(() => _youtubeAuth.RefreshToken());
-                if (!refreshed)
-                {
-                    TokenStore.Clear();
-                    AppLog.Write("Saved session could not be refreshed; signed out");
-                    _notifications.Info("Signed out of YouTube",
-                        "The saved session expired — sign in again when you next go live.");
-                    return;
-                }
-            }
-
-            IsConnected = true;
-            SyncConnectedAccount();
-        }
-        catch (Exception ex)
-        {
-            AppLog.Write($"LoadSavedSessionAsync failed: {ex}");
-        }
-    }
-
-    private void SyncConnectedAccount()
-    {
-        var channel = _youtubeAuth.CurrentChannel;
-        AccountAvatarUrl = channel?.ProfileImageUrl ?? string.Empty;
-        AccountDisplayName = channel?.DisplayName ?? string.Empty;
-    }
-
-    // ─── TASK 10 — Polar license validation ───
-
-    /// <summary>At startup, load the cached license state and re-validate online
-    /// if a key exists. If offline and within the 14-day grace period, the cached
-    /// premium state is trusted. If the grace period is exceeded, premium lapses.</summary>
-    private async Task ValidateLicenseAtStartupAsync()
-    {
-        var savedKey = _layoutStore.LoadLicenseKey();
-        if (string.IsNullOrWhiteSpace(savedKey))
-        {
-            IsPremium = false;
-            return;
-        }
-
-        LicenseKey = savedKey;
-        var validatedAt = _layoutStore.LoadLicenseValidatedAt();
-        var cachedPremium = _layoutStore.LoadIsPremium();
-
-        // If the last validation was within the grace period, trust the cache
-        // while we attempt an online re-validation in the background.
-        if (validatedAt.HasValue && DateTime.UtcNow - validatedAt.Value < OfflineGracePeriod)
-        {
-            IsPremium = cachedPremium;
-        }
-
-        // Try an online check — if it succeeds, it overrides the cache.
-        try
-        {
-            var service = new PolarLicenseService();
-            var result = await service.ValidateAsync(savedKey);
-            if (result.IsValid)
-            {
-                IsPremium = true;
-                _layoutStore.SaveIsPremium(true);
-                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
-            }
-            else
-            {
-                // Key revoked or expired — clear premium.
-                IsPremium = false;
-                _layoutStore.SaveIsPremium(false);
-                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
-                AppLog.Write($"License validation failed: {result.Error}");
-                _notifications.Warning("Premium is no longer active",
-                    $"{result.Error} — watermark branding returns until the license is renewed.");
-            }
-        }
-        catch (Exception ex)
-        {
-            // Offline or network error — keep the cached state, log it.
-            AppLog.Write($"License re-validation skipped (offline?): {ex.Message}");
-            if (!validatedAt.HasValue || DateTime.UtcNow - validatedAt.Value >= OfflineGracePeriod)
-            {
-                IsPremium = false;
-                _layoutStore.SaveIsPremium(false);
-            }
-        }
-    }
-
-    /// <summary>Called from the Activate button in the About overlay. Validates
-    /// the entered key, persists it, and flips premium state.</summary>
-    private async Task ActivateLicenseAsync()
-    {
-        if (string.IsNullOrWhiteSpace(LicenseKey)) return;
-
-        IsLicenseValidating = true;
-        LicenseMessage = "Validating\u2026";
-
-        try
-        {
-            var service = new PolarLicenseService();
-            var result = await service.ValidateAsync(LicenseKey);
-            if (result.IsValid)
-            {
-                IsPremium = true;
-                _layoutStore.SaveLicenseKey(LicenseKey.Trim());
-                _layoutStore.SaveIsPremium(true);
-                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
-                LicenseMessage = "Premium activated! The watermark has been removed.";
-                AppLog.Write("License activated successfully");
-            }
-            else
-            {
-                IsPremium = false;
-                _layoutStore.SaveLicenseKey(null);
-                _layoutStore.SaveIsPremium(false);
-                LicenseMessage = result.Error ?? "Invalid license key.";
-                AppLog.Write($"License activation failed: {result.Error}");
-            }
-        }
-        catch (Exception ex)
-        {
-            LicenseMessage = $"Activation error: {ex.Message}";
-            AppLog.Write($"License activation error: {ex}");
-        }
-        finally
-        {
-            IsLicenseValidating = false;
-        }
-    }
-
     private static string DefaultLayoutPath => Path.Combine(
         Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
         "ytLlive",
@@ -2427,60 +2006,6 @@ public partial class MainViewModel : ViewModelBase
         }
     }
 
-    // ─── Auto-save wiring ───
-    private void OnScenesChanged(object? sender, NotifyCollectionChangedEventArgs e)
-    {
-        if (e.NewItems != null)
-            foreach (Scene scene in e.NewItems)
-                WireScene(scene);
-        if (e.OldItems != null)
-            foreach (Scene scene in e.OldItems)
-                UnwireScene(scene);
-        OnPropertyChanged(nameof(MissingScenes));
-        OnPropertyChanged(nameof(ShowAddScene));
-        ScheduleSave();
-    }
-
-    private void WireScene(Scene scene)
-    {
-        scene.PropertyChanged += OnScenePropertyChanged;
-        scene.Elements.CollectionChanged += OnElementsChanged;
-    }
-
-    private void UnwireScene(Scene scene)
-    {
-        scene.PropertyChanged -= OnScenePropertyChanged;
-        scene.Elements.CollectionChanged -= OnElementsChanged;
-    }
-
-    private void OnScenePropertyChanged(object? sender, PropertyChangedEventArgs e)
-    {
-        // A rename can drop a canonical scene in/out of MissingScenes.
-        OnPropertyChanged(nameof(MissingScenes));
-        OnPropertyChanged(nameof(ShowAddScene));
-        ScheduleSave();
-    }
-
-    private void OnElementsChanged(object? sender, NotifyCollectionChangedEventArgs e)
-    {
-        if (e.NewItems != null)
-            foreach (SceneElement element in e.NewItems)
-                element.PropertyChanged += OnElementPropertyChanged;
-        if (e.OldItems != null)
-            foreach (SceneElement element in e.OldItems)
-                element.PropertyChanged -= OnElementPropertyChanged;
-        OnPropertyChanged(nameof(CanAddWebcam));
-        OnPropertyChanged(nameof(CanAddYouTubeChat));
-        ScheduleSave();
-    }
-
-    private void OnElementPropertyChanged(object? sender, PropertyChangedEventArgs e)
-    {
-        if (sender is WebcamSceneConfig && e.PropertyName == nameof(SceneElement.IsVisible))
-            OnPropertyChanged(nameof(CanShowWebcamInStagedScene));
-        ScheduleSave();
-    }
-
     private void ScheduleSave()
     {
         if (_isLoading || _saveDebounce == null) return;
@@ -2488,23 +2013,6 @@ public partial class MainViewModel : ViewModelBase
         _saveDebounce.Start();
     }
 
-    // Adds a canonical scene by name — only when it's actually missing. The
-    // background flag follows the policy (Live yes, everyone else no).
-    private void AddScene(string name)
-    {
-        if (!SceneCatalog.IsCanonical(name)) return;
-        if (Scenes.Any(s => SceneCatalog.Is(s.Name, name))) return;
-        var scene = new Scene
-        {
-            Name = name.Trim(),
-            IsChatScene = SceneCatalog.IsChat(name),
-            HasBackground = SceneCatalog.HasBackground(name),
-        };
-        EnsureBackground(scene);
-        Scenes.Add(scene);
-        StagedScene = scene;
-    }
-
     // ─── Background model (TASK 25): exactly ONE Background per screen, index 0,
     // never removable or re-addable. Static default art on Starting/BRB/Chat/Ending;
     // on Live it's the capture-flavored row (Show Desktop / monitor switch /
@@ -2997,31 +2505,6 @@ public partial class MainViewModel : ViewModelBase
         Process.Start(new ProcessStartInfo(url) { UseShellExecute = true });
     }
 
-    // Runs the OAuth flow (browser + loopback callback) on a background thread.
-    // The resulting channel is returned to the caller and persisted via the
-    // auth service's sessionChanged hook.
-    private async Task<YouTubeChannel?> SignInAsync()
-    {
-        try
-        {
-            var channel = await Task.Run(() => _youtubeAuth.AuthenticateAsync());
-            if (channel == null)
-            {
-                _notifications.Warning("Sign-in was unsuccessful", "Please try again.");
-                return null;
-            }
-
-            IsConnected = true;
-            SyncConnectedAccount();
-            return channel;
-        }
-        catch (Exception ex)
-        {
-            _notifications.Error("Sign-in failed", ex.Message);
-            return null;
-        }
-    }
-
     private void OnChatMessageReceived(ChatMessage message)
     {
         System.Windows.Application.Current.Dispatcher.Invoke(() =>
@@ -3880,21 +3363,4 @@ public partial class MainViewModel : ViewModelBase
             ? SocialBarPosition.Bottom
             : SocialBarPosition.Top);
 
-    /// <summary>Signs out of YouTube (the delete-the-YouTube-slot action in the dialog).</summary>
-    private async Task SignOutYouTubeAsync()
-    {
-        _youtubeAuth.ClearSession();
-        TokenStore.Clear();
-        IsConnected = false;
-        SyncConnectedAccount();
-        NotifySocialsChanged();
-        AppLog.Write("Socials: signed out of YouTube");
-        await Task.CompletedTask;
-    }
-
-    private async Task ChangeAccountAsync()
-    {
-        await SignOutYouTubeAsync();
-        await SignInAsync();
-    }
     }

ViewModels/index.md

@@ -18,13 +18,31 @@ for what the ViewModels drive; base class in [`Helpers/ViewModelBase.cs`](../Hel
 ## MainViewModel partial split (in progress)
 
 `MainViewModel.cs` is being split into one file per functional area, zero behavior
-change, one commit per partial (each commit a roll-back point):
+change, one commit per partial (each commit a roll-back point). **Commit naming:**
+titles carry the series id (`Commit N/12`), tags are `refactor-commit-N` — e.g.
+`git show refactor-commit-1`. Every partial lands with a `ViewModels/index.md`
+update in the SAME commit.
+
+Progress (Commit N/12 · tag):
+- **Commit 1/12 · `refactor-commit-1`: Account landed** → `MainViewModel.Account.cs`
+  (session restore `LoadSavedSessionAsync`, sign-in/out/change account,
+  `IsConnected`/`AccountAvatarUrl`/`AccountDisplayName`/`AccountStatusLightToolTip`).
+- **Commit 2/12 · `refactor-commit-2`: License landed** → `MainViewModel.License.cs`
+  (Polar license state: `LicenseKey`/`LicenseMessage`/`IsLicenseValidating`/
+  `IsLicenseEntryOpen`/`IsHubVisible`/`IsPremium`, `OfflineGracePeriod`,
+  `ValidateLicenseAtStartupAsync`, `ActivateLicenseAsync`).
+- **Commit 3/12 · `refactor-commit-3`: Scenes landed** → `MainViewModel.Scenes.cs`
+  (`Scenes` + `StagedScene`/`LiveScene`/`IsEditMode`, transitions
+  `SelectedTransitionType`/`TransitionDurationMs`/`TransitionToScene`/
+  `ApplyTransitionToLive`, global hotkeys `HandleHotkey`/`OpenHotkeyConfig`/
+  `RefreshHotkeyLabels`, scene-gating hints, `MissingScenes`/`ShowAddScene`/
+  `CanChangeBackground`, scene wiring `OnScenesChanged`/`WireScene`/`UnwireScene`,
+  `AddScene`).
 
 - Core file keeps: fields, ctor, `Shutdown`/`SaveLayoutNow`/`ScheduleSave`/`LoadLayout`,
   `SetPanel`/`ShowOverlay`/`ShowLicenses`, `CreateBrush`, `OpenUrl`/`ComposeEmail`,
   `SubmitBug`/`SubmitFeature`, window-geometry pass-through.
-- Partials: `Account` (sign-in/session/avatar), `License` (Polar key validation + `IsPremium`),
+- Partials: `Account` ✔ (Commit 1), `License` ✔ (Commit 2), `Scenes` ✔ (Commit 3), `Background` (background model + screen
-  `Scenes` (scene catalog + hotkeys + transitions), `Background` (background model + screen
   capture + display picker), `Webcam` (webcam identity + per-scene configs + captures),
   `Audio` (mic + game bars + TRAX), `Trax` (music player), `Socials` (social bar + dialog),
   `Streaming` (go-live/record + health + quality tiers + media source pipeline),