[GUI] Update library page layout (#690)

* [GUI] Add horizontal game tiles

* [GUI] Update launching elements layout

* [GUI] Change cards format to squares

src/SharpEmu.GUI/LibraryTile.cs

@@ -0,0 +1,9 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+namespace SharpEmu.GUI;
+
+/// <summary>
+/// Base type for game cards and actions shown in the library rail.
+/// </summary>
+public abstract class LibraryTile;