fix: prevent TUI StackOverflowException from excessive log controls

The TUI log view used an ItemsControl with 5000 max entries and no UI
virtualization. Avalonia's composition renderer traverses the entire
visual tree on each frame -- with thousands of TextBlock controls, the
recursive Render/RenderCore calls exceed the thread stack size on
constrained devices (especially ARM where each stack frame is larger
due to ABI differences), causing a StackOverflowException in
ServerCompositionContainerVisual.Render.

Changes:
- Enable VirtualizingStackPanel on the log ItemsControl so Avalonia
  only creates visuals for the rows currently in the viewport.
- Add [Console.General] TUI_Log_Scrollback config option so users can
  control max log lines in TUI mode. Default is 0 (automatic: 3000 on
  x86/x64, 500 on ARM/ARM64).

Made-with: Cursor

MinecraftClient/Settings.cs

@@ -1218,6 +1218,9 @@ namespace MinecraftClient
 
                     [TomlInlineComment("$Console.General.History_Input_Records$")]
                     public int History_Input_Records = 32;
+
+                    [TomlInlineComment("$Console.General.TUI_Log_Scrollback$")]
+                    public int TUI_Log_Scrollback = 0;
                 }
 
                 [TomlDoNotInlineObject]