Dynamic App Icon for MacOS

Initial attempt:
https://github.com/fastrepl/hyprnote/commit/fc90854111f228f26802299d3a2962ed28e2a713
(not work. got tauri commands not found for some reason, tried calling rust code directly in desktop2/lib.rs, but no error, no change to icon. `pnpm -F desktop2 dev`)

Related:
https://github.com/tauri-apps/tauri/issues/2985#issuecomment-987308498