refactor: split Account out of MainViewModel — Commit 1/12 (tag refactor-commit-1)

Pure member movement into MainViewModel.Account.cs (zero behavior change):
session restore (LoadSavedSessionAsync), sign-in/out/change (SignInAsync,
SignOutYouTubeAsync, ChangeAccountAsync), IsConnected + account avatar/name +
AccountStatusLightToolTip. Partial carries its own usings (ytLive.Services for
the INotificationService default interface methods). docs in same commit:
ViewModels/index.md split table + tagging convention.

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.cs

@@ -35,9 +35,6 @@ public partial class MainViewModel : ViewModelBase
     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;
@@ -535,37 +532,6 @@ 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. ───
@@ -1062,11 +1028,6 @@ 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;
@@ -1789,46 +1750,6 @@ 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
@@ -2997,31 +2918,6 @@ 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 +3776,4 @@ 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

@@ -18,12 +18,20 @@ 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`).
 
 - 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` (Polar key validation + `IsPremium`),
   `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),