feat: add RAII window class with OpenGL 4.1 context

- Add cbt::window class in cbt/ directory with RAII lifecycle
- Add setup_opengl and info_opengl for glad init and GL info
- Add Q key to quit the application
- Update CMakeLists.txt with glfw3 and glad dependencies
- Update AGENTS.md with snake_case naming and shell conventions

cbt/window.cpp

@@ -0,0 +1,92 @@
+#define GLFW_INCLUDE_NONE
+#include "GLFW/glfw3.h"
+
+#include "window.hpp"
+
+#include <string_view>
+
+#include "glad/glad.h"
+#include "fmt/std.h"
+
+namespace cbt {
+
+auto window::init() -> bool {
+    if (!glfwInit()) {
+        fmt::print("Failed to initialize GLFW\n");
+        return false;
+    }
+    return true;
+}
+
+auto window::terminate() -> void {
+    glfwTerminate();
+}
+
+auto window::setup_opengl() -> bool {
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
+        fmt::print("Failed to initialize GLAD\n");
+        return false;
+    }
+    info_opengl();
+    return true;
+}
+
+auto window::info_opengl() -> 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))));
+}
+
+window::window(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(static_cast<GLFWwindow*>(m_window));
+
+    if (!setup_opengl()) {
+        terminate();
+        return;
+    }
+}
+
+window::~window() {
+    if (m_window) {
+        glfwDestroyWindow(static_cast<GLFWwindow*>(m_window));
+    }
+    if (m_initialized) {
+        terminate();
+    }
+}
+
+auto window::should_close() const -> bool {
+    return m_window && glfwWindowShouldClose(static_cast<GLFWwindow*>(m_window));
+}
+
+auto window::valid() const -> bool {
+    return m_window != nullptr;
+}
+
+auto window::swap_buffers() -> void {
+    glfwSwapBuffers(static_cast<GLFWwindow*>(m_window));
+}
+
+auto window::poll_events() -> void {
+    glfwPollEvents();
+}
+
+}

cbt/window.hpp

@@ -0,0 +1,27 @@
+#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; }
+};
+
+}