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.

Models/AttentionAlert.cs

@@ -0,0 +1,35 @@
+namespace ytLive.Models;
+
+/// <summary>
+/// One row in the left panel's alert stack (creator design, 2026-11-05). The stack sits above the
+/// panel's content and pushes it down, so an alert is seen without hunting for a tab.
+/// <para><b>Pinned</b> rows are standing state, not errors to clear: they show a pin instead of a
+/// close control and are only removed when the state itself changes (the Steam licence indicator
+/// becomes dismissible — and its dismissal permanent — once ownership is verified).</para>
+/// <para>Clicking a row runs its action: the licence indicator opens About; an event alert opens the
+/// Logs tab with that event's lines highlighted.</para>
+/// </summary>
+public sealed record AttentionAlert(
+    string Id,
+    string Label,
+    string Text,
+    bool IsPinned,
+    AttentionAlertAction Action,
+    long LogFrom = 0,
+    long LogTo = 0)
+{
+    /// <summary>True while a close control should be shown (a dismissible row).</summary>
+    public bool CanDismiss => !IsPinned;
+
+    /// <summary>True while the row should show the pin glyph instead of a close control.</summary>
+    public bool ShowsPin => IsPinned;
+}
+
+public enum AttentionAlertAction
+{
+    /// <summary>Open the About panel (the licence indicator).</summary>
+    About,
+
+    /// <summary>Open the Logs tab and highlight this event's lines.</summary>
+    Logs,
+}