damageRing: move to hyprland impl

A small wlroots utility we were still using.

src/helpers/DamageRing.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "./math/Math.hpp"
+#include <array>
+
+constexpr static int DAMAGE_RING_PREVIOUS_LEN = 2;
+
+class CDamageRing {
+  public:
+    void    setSize(const Vector2D& size_);
+    bool    damage(const CRegion& rg);
+    void    damageEntire();
+    void    rotate();
+    CRegion getBufferDamage(int age);
+    bool    hasChanged();
+
+  private:
+    Vector2D                                      size;
+    CRegion                                       current;
+    std::array<CRegion, DAMAGE_RING_PREVIOUS_LEN> previous;
+    size_t                                        previousIdx = 0;
+};