feat: add OpenGL abstraction layer with RAII resources

- Replace window class with cbt::opengl::context
- Add buffer resource (VBO, EBO, UBO, SSBO) with move semantics
- Add texture resource with format/type enums and filtering
- Add descriptor_set for Vulkan-style resource binding
- All resources use RAII with proper cleanup

cbt/window.hpp

@@ -1,27 +0,0 @@
-#pragma once
-
-#include <string>
-
-namespace cbt {
-
-class window {
-    void* m_window = nullptr;
-    bool m_initialized = false;
-
-    static auto init() -> bool;
-    static auto terminate() -> void;
-    static auto setup_opengl() -> bool;
-    static auto info_opengl() -> void;
-
-public:
-    explicit window(std::string title, int width, int height);
-    ~window();
-
-    auto should_close() const -> bool;
-    auto valid() const -> bool;
-    auto swap_buffers() -> void;
-    auto poll_events() -> void;
-    auto raw() const -> void* { return m_window; }
-};
-
-}