feat(top bar): EDIT decides live vs test on the primary button — the TEST button is gone

Creator ruling (2026-10-30):
- EDIT off + ON-AIR armed → the primary button reads "Go Live" and runs the livestream.
- EDIT on + ON-AIR armed → the same button reads "Test Stream" and runs the test broadcast.
- REC armed (or nothing armed) → "Start Recording", whatever EDIT says; there is no test
  recording, and an unarmed start records locally rather than doing nothing.

So the fifth button was redundant: `ShowTestButton` no longer feeds any control. The decision is a
pure function (`Models/SessionStartDecision`) so the whole matrix is testable without a window;
`PrimaryStartCommand` follows the same kind, so label and action cannot disagree.

Guard: SessionStartDecisionTests pins the four cases, including the no-dead-ends fallback that my
first version got wrong (unarmed returned Live instead of Record — the test caught it).

Note for the v1 gate: the "hide TEST at v1" item is now satisfied by construction — the test path
is a mode of the primary button, not a separate control.

Controls/TopBar.xaml

@@ -100,15 +100,10 @@
                 <!-- Go face names the world: "Start Recording" vs "Go Live".
                      (Signed-out ON-AIR Start routes to the sign-in — StartSession.) -->
                 <Button Content="{Binding PrimaryStartButtonLabel}" Style="{StaticResource YtButton}"
-                        Height="32" Margin="10,0,0,0" Command="{Binding StartStreamCommand}"
+                        Height="32" Margin="10,0,0,0" Command="{Binding PrimaryStartCommand}"
                         Visibility="{Binding ShowPrimaryStartButton, Converter={StaticResource BoolToVis}}"/>
-                <!-- Test is a child of Stream — a dry-run of the livestream, so it
-                     exists only inside the Stream world (stream armed + signed in). -->
-                <Button Content="Test" Style="{StaticResource YtButtonSecondary}" Padding="12,4" FontSize="11"
-                        Height="32" Margin="8,0,0,0" VerticalAlignment="Center"
-                        Command="{Binding StartTestCommand}"
-                        ToolTip="Run a private test broadcast to check your chat overlay."
-                        Visibility="{Binding ShowTestButton, Converter={StaticResource BoolToVis}}"/>
+                <!-- No separate TEST button (creator ruling 2026-10-30): EDIT decides whether
+                     the ON-AIR start is the real livestream or the test one. -->
             </StackPanel>
 
             <!-- RUNNING: one reality line (dot + word + elapsed) and the stop -->

Models/SessionStartDecision.cs

@@ -0,0 +1,38 @@
+namespace ytLive.Models;
+
+/// <summary>What the top bar's primary action button will do.</summary>
+public enum SessionStartKind
+{
+    Record,
+    Live,
+    Test,
+}
+
+/// <summary>Creator ruling (2026-10-30): the primary button is context-sensitive, so the separate
+/// TEST button is gone.
+///
+/// <list type="bullet">
+/// <item>EDIT off + ON-AIR armed → Go Live (the livestream message)</item>
+/// <item>EDIT on + ON-AIR armed → Test Stream (the test-livestream message) — a dry run you
+/// cannot leak, because every broadcast is private pre-v1 anyway</item>
+/// <item>REC armed → Start Recording, whatever EDIT says (there is no test recording)</item>
+/// </list>
+///
+/// <para>Pure so the whole matrix is testable without a window.</para></summary>
+public static class SessionStartDecision
+{
+    public static SessionStartKind For(bool recordArmed, bool onAirArmed, bool editing)
+    {
+        // Neither pill armed still starts something: local recording needs no account, and the
+        // no-dead-ends rule forbids an inert primary button.
+        if (recordArmed || !onAirArmed) return SessionStartKind.Record;
+        return editing ? SessionStartKind.Test : SessionStartKind.Live;
+    }
+
+    public static string LabelFor(SessionStartKind kind) => kind switch
+    {
+        SessionStartKind.Record => "Start Recording",
+        SessionStartKind.Test => "Test Stream",
+        _ => "Go Live",
+    };
+}

ViewModels/MainViewModel.Scenes.cs

@@ -85,8 +85,12 @@ public partial class MainViewModel
         get => _editingActive;
         set
         {
-            if (SetProperty(ref _editingActive, value))
-                OnPropertyChanged(nameof(IsEditMode));
+            if (!SetProperty(ref _editingActive, value)) return;
+            OnPropertyChanged(nameof(IsEditMode));
+            // EDIT decides whether the ON-AIR start is live or a test (creator ruling 2026-10-30).
+            OnPropertyChanged(nameof(PrimaryStartKind));
+            OnPropertyChanged(nameof(PrimaryStartButtonLabel));
+            OnPropertyChanged(nameof(PrimaryStartCommand));
         }
     }
 

ViewModels/MainViewModel.Streaming.cs

@@ -72,6 +72,9 @@ public partial class MainViewModel : ViewModelBase
                 OnPropertyChanged(nameof(OnAirBrush));
                 OnPropertyChanged(nameof(IsLivePrivate));
                 OnPropertyChanged(nameof(ShowPrimaryStartButton));
+            OnPropertyChanged(nameof(PrimaryStartKind));
+            OnPropertyChanged(nameof(PrimaryStartButtonLabel));
+            OnPropertyChanged(nameof(PrimaryStartCommand));
                 OnPropertyChanged(nameof(ShowEndStreamButton));
                 OnPropertyChanged(nameof(EndButtonText));
                 OnPropertyChanged(nameof(ShowTestButton));
@@ -109,6 +112,9 @@ public partial class MainViewModel : ViewModelBase
             if (!SetProperty(ref _recordPillOn, value)) return;
             if (value && _onAirPillOn) OnAirPillOn = false; // record-OR-live — arming REC drops ON-AIR
             OnPropertyChanged(nameof(ShowPrimaryStartButton));
+            OnPropertyChanged(nameof(PrimaryStartKind));
+            OnPropertyChanged(nameof(PrimaryStartButtonLabel));
+            OnPropertyChanged(nameof(PrimaryStartCommand));
             OnPropertyChanged(nameof(CanStartSession));
             RaiseTopBarModes();
         }
@@ -125,6 +131,9 @@ public partial class MainViewModel : ViewModelBase
             if (!SetProperty(ref _onAirPillOn, value)) return;
             if (value && _recordPillOn) RecordPillOn = false; // record-OR-live — arming ON-AIR drops REC
             OnPropertyChanged(nameof(ShowPrimaryStartButton));
+            OnPropertyChanged(nameof(PrimaryStartKind));
+            OnPropertyChanged(nameof(PrimaryStartButtonLabel));
+            OnPropertyChanged(nameof(PrimaryStartCommand));
             OnPropertyChanged(nameof(CanStartSession));
             RaiseTopBarModes();
         }
@@ -146,6 +155,9 @@ public partial class MainViewModel : ViewModelBase
             OnPropertyChanged(nameof(IsEditMode));
             OnPropertyChanged(nameof(ShowEndStreamButton));
             OnPropertyChanged(nameof(ShowPrimaryStartButton));
+            OnPropertyChanged(nameof(PrimaryStartKind));
+            OnPropertyChanged(nameof(PrimaryStartButtonLabel));
+            OnPropertyChanged(nameof(PrimaryStartCommand));
             OnPropertyChanged(nameof(EndButtonText));
             OnPropertyChanged(nameof(ShowTestButton));
             RaiseTopBarModes();
@@ -169,8 +181,18 @@ public partial class MainViewModel : ViewModelBase
     /// routes to the sign-in inside StartSession (Start — the account step shows up
     /// beside it as the Sign In button); a signed-out go-live stays the dead-end the
     /// creator ruling 2026-09-20-02 forbids.</summary>
-    public string PrimaryStartButtonLabel =>
-        OnAirPillOn ? "Go Live" : "Start Recording";
+    /// <summary>Creator ruling 2026-10-30: EDIT decides whether the ON-AIR start is the real
+    /// livestream or the test one, which is why the separate TEST button is gone.</summary>
+    public SessionStartKind PrimaryStartKind =>
+        SessionStartDecision.For(RecordPillOn, OnAirPillOn, EditingActive);
+
+    public string PrimaryStartButtonLabel => SessionStartDecision.LabelFor(PrimaryStartKind);
+
+    /// <summary>The button's action follows its label: Test runs the same go-live pipeline with
+    /// `IsTestStream` set, Go Live runs it for real.</summary>
+    public ICommand PrimaryStartCommand => PrimaryStartKind == SessionStartKind.Test
+        ? StartTestCommand
+        : StartStreamCommand;
 
     /// <summary>The End button shows while recording OR live.</summary>
     public bool ShowEndStreamButton => IsLive || IsRecording;

ytLive.Tests/SessionStartDecisionTests.cs

@@ -0,0 +1,32 @@
+using Xunit;
+using ytLive.Models;
+
+namespace ytLive.Tests;
+
+/// <summary>Creator ruling (2026-10-30): the top bar's primary button is context-sensitive and the
+/// separate TEST button is gone.
+///
+/// <para>EDIT off + ON-AIR → the livestream message. EDIT on + ON-AIR → the test-livestream
+/// message. REC always records, because there is no test recording. The matrix is pure, so it is
+/// cheaper to pin it here than to drive a window.</para></summary>
+public class SessionStartDecisionTests
+{
+    [Fact]
+    public void Edit_decides_whether_the_on_air_start_is_live_or_a_test()
+    {
+        // ON-AIR armed: EDIT decides.
+        Assert.Equal(SessionStartKind.Live, SessionStartDecision.For(recordArmed: false, onAirArmed: true, editing: false));
+        Assert.Equal("Go Live", SessionStartDecision.LabelFor(SessionStartKind.Live));
+
+        Assert.Equal(SessionStartKind.Test, SessionStartDecision.For(recordArmed: false, onAirArmed: true, editing: true));
+        Assert.Equal("Test Stream", SessionStartDecision.LabelFor(SessionStartKind.Test));
+
+        // REC armed: always a recording, whatever EDIT says (no test recording exists).
+        Assert.Equal(SessionStartKind.Record, SessionStartDecision.For(true, false, false));
+        Assert.Equal(SessionStartKind.Record, SessionStartDecision.For(true, false, true));
+        Assert.Equal("Start Recording", SessionStartDecision.LabelFor(SessionStartKind.Record));
+
+        // Unarmed start records locally (the no-dead-ends rule).
+        Assert.Equal(SessionStartKind.Record, SessionStartDecision.For(false, false, false));
+    }
+}