fix: webcam identity->device key for output frames; top bar always has a Start; light-pill grouping

Take two (2026-09-01) three confirmed defects, all from creator feedback + the
new resolver logging:

1. NO WEBCAM IN OUTPUT: WebcamSceneConfig.WebcamId carries the identity GUID;
   CameraManager keys sessions by DEVICE id — GetLatestFrame(guid) returned null
   forever, the compositor silently dropped the layer while the preview (bitmap
   path) looked fine. The resolver logging added in 8dcaee0 caught it red-handed.
   DeviceKeyForWebcam maps identity->device through the _webcam singleton (identity
   mismatch / unknown ids pass through). Test: WebcamOutputKeyTests.

2. START BUTTON VANISHED AFTER STOP: my pills-clear ruling met the old
   ShowPrimaryStartButton gate (needed IsConnected or a lit REC pill) — signed-out,
   pills-off = blank top bar, no session reachable. Start is now ALWAYS the idle
   face; unarmed Start records (local needs no account — no dead-end no-op); the
   Sign In button folds into Start's context menu ('Sign in to YouTube', shown while
   disconnected) with a dedicated SignInCommand. SessionTeardownTests extended:
   stopped session must leave a reachable Start.

3. TOP BAR ORDER (creator spec): [sign light] REC [pill]  [sign light] ON-AIR [pill]
   — each reality lamp now sits in front of its own intent switch (was: two pills,
   then two orphaned dots). Sign labels keep the shared StatusSignText style.

Tests: WebcamOutputKey, SessionTeardown, FramePump, WebcamMenuGate, GlobalHotkey,
BroadcastPullOut — 14/14 across the six classes, clean build 0 warnings.

ViewModels/MainViewModel.Streaming.Operations.cs

@@ -21,7 +21,15 @@ public partial class MainViewModel : ViewModelBase
         if (IsLive || IsRecording) return;
         var streaming = OnAirPillOn;
         var recording = RecordPillOn;
-        if (!streaming && !recording) return;
+        if (!streaming && !recording)
+        {
+            // Nothing armed = "record something" (local recording needs no account,
+            // 2026-09-01): a Start that silently no-ops is the dead end the design
+            // principle forbids. The pill lights so reality and intent agree.
+            RecordPillOn = true;
+            BeginRecordOnly();
+            return;
+        }
 
         if (!streaming)
         {

ViewModels/MainViewModel.Streaming.cs

@@ -60,7 +60,6 @@ public partial class MainViewModel : ViewModelBase
                 OnPropertyChanged(nameof(OnAirBrush));
                 OnPropertyChanged(nameof(IsLivePrivate));
                 OnPropertyChanged(nameof(ShowPrimaryStartButton));
-                OnPropertyChanged(nameof(ShowLogInButton));
                 OnPropertyChanged(nameof(ShowEndStreamButton));
                 OnPropertyChanged(nameof(EndButtonText));
                 OnPropertyChanged(nameof(AccountStatusLightToolTip));
@@ -127,12 +126,12 @@ public partial class MainViewModel : ViewModelBase
         }
     }
 
-    /// <summary>The primary button shows when there's something to start, but never
-    /// while a session is running — once recording/live the ONLY control is the End
-    /// button.</summary>
-    public bool ShowPrimaryStartButton =>
-        IsOffline && !IsRecording && !IsLive
-        && (IsConnected || (RecordPillOn && !OnAirPillOn));
+    /// <summary>The primary button is ALWAYS the idle face of the top bar (2026-09-01):
+    /// stopping a session used to hide every start affordance (pills clear on stop,
+    /// and the old gate needed a sign-in or a lit pill — signed-out creators found a
+    /// blank bar). No dead ends: an unarmed Start records (local needs no account);
+    /// sign-in lives in the Start context menu.</summary>
+    public bool ShowPrimaryStartButton => IsOffline && !IsRecording;
 
     /// <summary>Either output selected makes the button actionable.</summary>
     public bool CanStartSession => RecordPillOn || OnAirPillOn;
@@ -144,8 +143,6 @@ public partial class MainViewModel : ViewModelBase
     /// "Stop Recording", while live "End Stream".</summary>
     public string EndButtonText => IsRecording && !IsLive ? "Stop Recording" : "End Stream";
 
-    public bool ShowLogInButton => !IsConnected && IsOffline && !IsRecording;
-
     public StreamHealth CurrentHealth
     {
         get => _currentHealth;
@@ -320,6 +317,7 @@ public partial class MainViewModel : ViewModelBase
 
     public ICommand StartStreamCommand { get; }
     public ICommand EndStreamCommand { get; }
+    public ICommand SignInCommand { get; }
     public ICommand ChooseRecordFolderCommand { get; }
     public ICommand ResetRecordFolderCommand { get; }
 }

ViewModels/MainViewModel.cs

@@ -211,6 +211,7 @@ public partial class MainViewModel : ViewModelBase
         OpenPremiumCommand = new RelayCommand(_ => OpenUrl(PremiumUrl), _ => IsPremiumAvailable);
         OpenLicensesCommand = new RelayCommand(_ => ShowLicenses());
         StartStreamCommand = new RelayCommand(_ => StartSession());
+        SignInCommand = new RelayCommand(_ => _ = SignInAsync(), _ => !IsConnected);
         EndStreamCommand = new RelayCommand(_ => StopStream(), _ => IsLive || IsRecording);
         ChooseRecordFolderCommand = new RelayCommand(_ => ChooseRecordFolder());
         ResetRecordFolderCommand = new RelayCommand(_ => ResetRecordFolder());
@@ -478,11 +479,24 @@ public partial class MainViewModel : ViewModelBase
 
     private DateTime _lastWebcamNullLog = DateTime.MinValue;
 
+    /// <summary>Maps a config's identity GUID to the CameraManager session key (the
+    /// DEVICE id). internal = test seam. Take-2 fix: looking up the identity GUID
+    /// against a device-keyed dictionary returned null forever.</summary>
+    internal string DeviceKeyForWebcam(string webcamId) =>
+        _webcam is { } w && w.Id == webcamId && !string.IsNullOrWhiteSpace(w.DeviceId)
+            ? w.DeviceId
+            : webcamId;
+
     private VideoFrame? ResolveOutputFrameCore(SceneElement element)
     {
         return element switch
         {
-            WebcamSceneConfig webcam => _cameraManager.GetLatestFrame(webcam.WebcamId),
+            // CameraManager sessions are keyed by DEVICE id (AcquireAsync(_webcam.DeviceId));
+            // configs carry the identity GUID (WebcamSceneConfig.WebcamId = _webcam.Id).
+            // Looking up by the GUID returned null forever — the webcam was structurally
+            // invisible on the output while the preview (bitmap path) looked fine
+            // (caught by the resolver logging, 2026-09-01 take two).
+            WebcamSceneConfig webcam => _cameraManager.GetLatestFrame(DeviceKeyForWebcam(webcam.WebcamId)),
             Source { IsLiveCapture: true, CaptureKey: not null } live => _screenCaptureManager.GetLatestFrame(live.CaptureKey),
             Source { Type: SourceType.ChatBox } chatBox => RenderChatBox(chatBox),
             Source { Type: SourceType.WebSource } web => _webView2Manager?.GetLatestFrame(web.Id),