Allow embedding fonts in mscz file

Your idea

There are a lot of instances when sharing a mscz file with friends and opening on their PC will result in missing fonts, because the author used a font that is not available on every system. The used has no way of knowing of this issue.

There is already a request to notify the user about missing fonts (see https://github.com/musescore/MuseScore/issues/17945).

As a second useful thing, because mscz is a zip file, I propose to introduce an option to embed the used fonts in the mscz file itself (if the user chooses to do so), so that the file can be opened on any PC withouth requiring the fonts to be previously installed.

Problem to be solved

Inconsistency when sharing a mscz file with fonts not available on the system.
Users must manually find out which fonts they need to properly display the score.

Prior art

No response

Additional context

No response

Checklist

• This request follows the guidelines for reporting issues
• I have verified that this feature request has not been logged before, by searching the issue tracker for similar requests

Start by reviewing how MuseScore packages and opens mscz ZIP files, then determine how a score identifies the fonts it uses. Define the user-facing opt-in behavior, font licensing constraints, and fallback handling before implementation; done means a shared mscz opens with its embedded fonts on a system where they are not installed.