fix(camera): reset camera on resize events and fix input handling on imgui toggle

- Add Camera::player() accessor.
- Handle WindowResizeEvent and FrameBufferResizeEvent to reset camera.
- Fix escape key handling to disable mouse before toggling imgui.
- Fix left alt handling to toggle mouse state correctly.
- Reset player key status when toggling imgui.

include/Cubed/camera.hpp

@@ -49,6 +49,7 @@ public:
     void change_perspective();
     bool is_first_person() const;
     bool handle_event(const Event& e);
+    ClientPlayer* player();
 };
 
 } // namespace Cubed