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/opengl/context.cpp

@@ -0,0 +1,97 @@
+#define GLFW_INCLUDE_NONE
+#include "GLFW/glfw3.h"
+
+#include "cbt/opengl/context.hpp"
+
+#include <string_view>
+
+#include "glad/glad.h"
+#include "fmt/std.h"
+
+namespace cbt::opengl {
+
+auto context::init() -> bool {
+    if (!glfwInit()) {
+        fmt::print("Failed to initialize GLFW\n");
+        return false;
+    }
+    return true;
+}
+
+auto context::terminate() -> void {
+    glfwTerminate();
+}
+
+auto context::setup_gl() -> bool {
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
+        fmt::print("Failed to initialize GLAD\n");
+        return false;
+    }
+    print_info();
+    return true;
+}
+
+auto context::print_info() -> void {
+    fmt::print("OpenGL Info:\n");
+    fmt::print("  vendor  | {}\n", std::string_view(reinterpret_cast<const char*>(glGetString(GL_VENDOR))));
+    fmt::print("  renderer| {}\n", std::string_view(reinterpret_cast<const char*>(glGetString(GL_RENDERER))));
+    fmt::print("  version | {}\n", std::string_view(reinterpret_cast<const char*>(glGetString(GL_VERSION))));
+    fmt::print("  glsl    | {}\n", std::string_view(reinterpret_cast<const char*>(glGetString(GL_SHADING_LANGUAGE_VERSION))));
+    fmt::print("\n");
+}
+
+context::context(std::string title, int width, int height) {
+    if (!init()) {
+        return;
+    }
+    m_initialized = true;
+
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+
+    m_window = glfwCreateWindow(width, height, title.c_str(), nullptr, nullptr);
+    if (!m_window) {
+        fmt::print("Failed to create window\n");
+        terminate();
+        return;
+    }
+
+    glfwMakeContextCurrent(m_window);
+
+    if (!setup_gl()) {
+        terminate();
+        return;
+    }
+}
+
+context::~context() {
+    if (m_window) {
+        glfwDestroyWindow(m_window);
+    }
+    if (m_initialized) {
+        terminate();
+    }
+}
+
+auto context::should_close() const -> bool {
+    return m_window && glfwWindowShouldClose(m_window);
+}
+
+auto context::valid() const -> bool {
+    return m_window != nullptr;
+}
+
+auto context::swap_buffers() -> void {
+    glfwSwapBuffers(m_window);
+}
+
+auto context::poll_events() -> void {
+    glfwPollEvents();
+}
+
+auto context::raw() const -> GLFWwindow* {
+    return m_window;
+}
+
+}