selection: Create it's dedicated class

includes/selection.hpp

@@ -0,0 +1,32 @@
+/*
+* File name: selection.hpp
+* Author: lejulien
+* Date created: 01-01-1970 00:59:59
+// Date modified: 12-01-2026 21:30:10
+* ------
+*/
+
+#pragma once
+
+#include <context.hpp>
+
+#include <imgui.h>
+#include <raylib.h>
+#include <rlImGui.h>
+
+namespace gol {
+
+class Selection {
+public:
+  Selection(std::shared_ptr<ctx>);
+  ~Selection() = default;
+  void update();
+  void display();
+private:
+  std::shared_ptr<ctx> context_ = nullptr;
+  Vector2 sel_pos_ = {0., 0.};
+  Vector2 mouse_pos_ = {0., 0.};
+  bool selecting_ = false;
+};
+
+} // namespace gol