feat(ui): left-panel alert stack — licence indicator pinned on top, events LIFO below

Creator design (2026-11-05). A stack of red rows at the top of the left panel, above both mode grids
so it shows while editing and while live, pushing the panel's content down.

- Row 1 is the **Steam licence indicator** and nothing displaces it. It reads as status, not a
  warning: "Entitlement 30 fps · Maximum 60 fps", both numbers derived from QualityOptions and
  HasProOutput. While higher tiers are unavailable it shows a **pin** (standing indicator, no close
  control); once ownership is verified the pin becomes a **close control** and the dismissal is
  persisted (`Steam.LicenceIndicatorDismissed`), permanent while ownership holds. Losing ownership
  restores it as pinned — a change of state, not a preference. Click → About.
- **Event rows stack beneath, newest first**, one row per episode (an episode advancing its state
  updates its own row rather than adding another). Each is dismissible. Click → the Logs tab opens
  with that event's sequence range painted red (`HighlightedLogFrom/To` + `LogInRangeConverter`; two
  numbers rather than a collection because the log list is virtualised and realised rows do not
  re-evaluate on membership changes).
- Replaces the old red panel under the quality picker, which is removed.
- The Steam diagnostic text loses "Contact the creator or support" for a neutral
  "Steam licensing is not configured in this build."

Tests: `AttentionAlertStackTests` — pinned first with the status text; owned → closable and the close
survives a reload but ownership loss restores it pinned; pinned cannot be dismissed; event rows LIFO
with in-place episode updates; clicking an event opens Logs and sets its range. AboutHub + Entitlement
tests updated for the removed panel and the new wording. FAST gate: 532 passed, 0 failed, 0 warnings.

ytLive.Tests/EntitlementTests.cs

@@ -22,7 +22,9 @@ public class EntitlementTests
     {
         var entitlement = SteamEntitlement.NotConfigured();
         Assert.False(entitlement.IsAppOwned);
-        Assert.Contains("paid Steam app ID is not configured", entitlement.ErrorMessage);
+        // The diagnostic is deliberately neutral (2026-11-05): the licence state is shown to the
+        // creator as a status indicator, so the log text carries no "contact support" wording.
+        Assert.Contains("Steam licensing is not configured", entitlement.ErrorMessage);
     }
 
     [Fact]