feat(ux): show notification on chat log draw failure (F7.1)

Surfaces a per-session warning notification when DrawChatLog throws so
the user knows something went wrong instead of staring at an empty
window. Stack trace stays in /xllog as before. The one-shot guard
prevents the notification stack from flooding frame-by-frame; it
resets only on the next plugin reload.

HellionChat/Ui/ChatLogWindow.cs

@@ -90,6 +90,10 @@ public sealed class ChatLogWindow : Window
     private bool PlayedClosingSound = true;
     private bool DrewThisFrame;
 
+    // F7.1: one-shot guard so a recurring draw failure doesn't spam the
+    // notification stack frame-by-frame. Resets only on next plugin reload.
+    private bool _notifiedDrawFailure;
+
     private long FrameTime; // set every frame
     internal long LastActivityTime = Environment.TickCount64;
 
@@ -627,6 +631,19 @@ public sealed class ChatLogWindow : Window
         catch (Exception ex)
         {
             Plugin.Log.Error(ex, "Error drawing Chat Log window");
+            if (!_notifiedDrawFailure)
+            {
+                Plugin.Notification.AddNotification(
+                    new Dalamud.Interface.ImGuiNotification.Notification
+                    {
+                        Title = "Hellion Chat",
+                        Content = "A drawing error occurred. Check /xllog for details.",
+                        Type = Dalamud.Interface.ImGuiNotification.NotificationType.Warning,
+                        InitialDuration = TimeSpan.FromSeconds(20),
+                    }
+                );
+                _notifiedDrawFailure = true;
+            }
             // Prevent recurring draw failures from constantly trying to grab
             // input focus, which breaks every other ImGui window.
             Activate = false;