feat(gui): Extract and modularize GUI system from main.cpp

- Create modular GUI architecture with base Panel class
- Implement GUIManager to handle window lifecycle and panel management
- Add Window wrapper class for SDL3/OpenGL context management
- Create specialized panels:
  - ConsolePanel: Colored log output with timestamps
  - CPUPanel: CPU debugging with tabs for registers, memory, and disassembly
  - PerformancePanel: Real-time FPS and frame time monitoring
- Apply modern dark theme with purple accents
- Add comprehensive menu bar (File, Emulation, View, Tools, Help)
- Update CMakeLists.txt to include new gui/ directory structure
- Refactor main.cpp to use the new GUI system
- Cutom theme on switch colors

gui/Window.h

@@ -0,0 +1,36 @@
+// Copyright 2025 Pound Emulator Project. All rights reserved.
+#pragma once
+
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_opengl.h>
+#include <memory>
+#include <string>
+
+namespace Pound::GUI
+{
+
+    class Window
+    {
+    public:
+        Window();
+        ~Window();
+
+        bool Initialize(const std::string &title, int width, int height);
+        void Shutdown();
+
+        SDL_Window *GetSDLWindow() const { return window; }
+        SDL_GLContext GetGLContext() const { return gl_context; }
+
+        bool ShouldClose() const { return should_close; }
+        void SetShouldClose(bool close) { should_close = close; }
+
+        void ProcessEvents();
+        void SwapBuffers();
+
+    private:
+        SDL_Window *window = nullptr;
+        SDL_GLContext gl_context = nullptr;
+        bool should_close = false;
+    };
+
+} // namespace Pound::GUI