style: move public members first in class declarations

- Reorder all class headers to put public interface before private members
- Document convention in AGENTS.md

cbt/opengl/context.hpp

@@ -8,14 +8,6 @@
 namespace cbt::opengl {
 
 class context {
-    GLFWwindow* m_window = nullptr;
-    bool m_initialized = false;
-
-    static auto init() -> bool;
-    static auto terminate() -> void;
-    static auto setup_gl() -> bool;
-    static auto print_info() -> void;
-
 public:
     explicit context(std::string title, int width, int height);
     ~context();
@@ -25,6 +17,15 @@ public:
     auto swap_buffers() -> void;
     auto poll_events() -> void;
     auto raw() const -> GLFWwindow*;
+
+private:
+    GLFWwindow* m_window = nullptr;
+    bool m_initialized = false;
+
+    static auto init() -> bool;
+    static auto terminate() -> void;
+    static auto setup_gl() -> bool;
+    static auto print_info() -> void;
 };
 
 }