Closes #ISSUE Fixed an issue where the first frame of the `Editing` page in onboarding would have a slight delay before rendering the first time it was navigated to. This was caused by listing the OS fonts on the main thread, blocking rendering. This PR fixes the issue by adding a new method to the font family cache to prefill the cache on a background thread. Release Notes: - N/A *or* Added/Fixed/Improved ... --------- Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com> Co-authored-by: Anthony Eid <hello@anthonyeid.me> Co-authored-by: Anthony <anthony@zed.dev>