Add DesktopProcess and start-gui command for launching GUI mode

Processes/DesktopProcess.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Threading;
+using Cosmos.Kernel.System.Graphics;
+using RemSox.Processing;
+using RemSox.UI.GUI.Rendering;
+using RemSox.UI.GUI.Windows;
+
+namespace RemSox.Processes;
+
+public class DesktopProcess : Process
+{
+    private static bool isGraphicsInitialized = false;
+
+    public static bool IsRunning { get; private set; } = false;
+
+    public DesktopProcess() : base("Desktop Manager")
+    {
+    }
+
+    internal override void Run()
+    {
+        IsRunning = true;
+
+        if (!isGraphicsInitialized)
+        {
+            WindowManager.AddRenderSource(new CanvasRenderSource());
+            isGraphicsInitialized = true;
+        }
+
+        // Trigger Canvas initialization
+        FullScreenCanvas.GetFullScreenCanvas();
+        
+        // Force existing windows to redraw onto the new canvas renderer
+        WindowManager.InvalidateAll();
+
+        while (!StopRequested)
+        {
+            WindowManager.Update();
+            
+            // Sleep slightly to yield CPU to the main CLI thread (approx 60 FPS)
+            Thread.Sleep(16);
+        }
+        
+        IsRunning = false;
+        
+        // Cosmos doesn't robustly support switching back to text mode yet.
+        // We will stop updating, but the screen will remain in graphics mode.
+    }
+}