Use platform windows for windowing instead of custom draggable window system

src/renderer/renderer.h

@@ -13,6 +13,13 @@ struct RendererDesc {
 };
 
 Renderer *renderer_create(RendererDesc *desc);
+
+// creates a lightweight renderer that shares the GPU device, pipeline, shaders, font atlas, and icon textures from a
+// parent renderer, but creates its own drawable surface (CAMetalLayer / swap chain), vertex/index buffers, and frame synchronization
+// primitives. On each renderer_begin_frame(), shared renderers sync font atlas updates from the parent so Cmd+/- zoom works across all
+// windows.
+Renderer *renderer_create_shared(Renderer *parent, RendererDesc *desc);
+
 void      renderer_destroy(Renderer *renderer);
 B32       renderer_begin_frame(Renderer *renderer);
 void      renderer_end_frame(Renderer *renderer, Clay_RenderCommandArray render_commands);