branding credit: run in every scene and in recordings, not only while live

Creator 2026-09-26: "the made with llamacasty flash should appear in all scenes,
not just live" and "should also appear in recordings". The presenter was
Start()/Stop()-ed from UpdateLiveVisuals()'s IsLive branch, so a recording made
WITHOUT ever going live carried no credit at all -- the exact case the creator hit
while judging compositing from local recordings.

It is now Start()ed once in the MainViewModel ctor and never stopped on live-state
churn. One start covers every scene, the preview, the stream and the recording,
because go-live and local recording are the SAME FramePump: both
Streaming.Operations.cs:68 and :199 call StartAsync with the same brandFlash:
delegate. Verified by reading both call sites, not assumed -- there is no second
encoder path that needed a "redirect". The licence gate needs no live branch at
all: IsPremium's setter already pushes BrandFlashPresenter.Enabled from anywhere.

Fixed a trap that app-lifetime exposed: Enabled = false stops the presenter's
DispatcherTimer to cut the advertisement mid-credit. When Start() was per-go-live
the next go-live restarted it; with a single app-lifetime Start() nothing would,
so a key entered mid-session would leave the credit dead until the process was
restarted. The setter now restarts the timer when re-enabling while _running.

Tests (12 facts in BrandFlashOutputTests, +2):
  Credit_IsComposited_WithNoLiveSession_AndSoARecordingCarriesIt -- drives a real
    never-live VM past the 5s first-flash delay and asks the frame the pump would
    composite. Uses a new internal AdvanceBrandFlash seam; because Advance only
    advances the cadence while the presenter is running, a credit coming out
    proves Start() happened at construction.
  ADowngradeMidSession_RestartsTheCadenceTimer -- asserts the premium/downgrade
    edge decision directly (IsCadenceTimerEnabled) instead of sleeping through a
    30-60s interval, which a synchronous test body cannot observe.

Full suite 364/364.

ViewModels/MainViewModel.Streaming.Operations.cs

@@ -429,18 +429,15 @@ public partial class MainViewModel : ViewModelBase
         PreviewGlowBrush = live ? IsTestStream ? "#9c6f1c" : "#e94560" : "Transparent";
         PreviewGlowThickness = live ? new Thickness(3) : new Thickness(0);
 
-        if (live)
-        {
-            // Cadence lives in the presenter: first credit 5s after go-live, then
-            // every rand(30s)+30s. It refuses to emit while premium.
-            _brandFlash.Enabled = !IsPremium;
-            _brandFlash.Start();
-        }
-        else
-        {
-            _healthPollTimer.Stop();
-            _brandFlash.Stop();
-        }
+        if (!live) _healthPollTimer.Stop();
+
+        // NOTE: the branding credit is deliberately NOT started/stopped here.
+        // CREATOR RULING 2026-09-26 — it must appear in EVERY scene and in
+        // recordings, not only while streaming. It used to be gated on IsLive, which
+        // meant a recording made without ever going live carried no credit at all.
+        // The presenter is started once for the life of the app (MainViewModel ctor);
+        // the licence gate rides on BrandFlashPresenter.Enabled via IsPremium, so it
+        // needs no live branch — IsPremium's setter pushes it from any thread.
         UpdateSessionTimer();
     }