Page numbers and headers have merged entities, Page Numbers in Text Styles cannot affect frames at all

Issue type

UX/Interaction bug (incorrect behaviour)

Description with steps to reproduce

1. Create a score with multiple pages
2. Format -> Style -> Text Styles -> Header -> Frame: Rectangle
   Expectation: Only the Header gets a frame.
   Reality: The Page Numbers also get a frame, even if you specify in Text Styles that Page Numbers should not have frames.

Supporting files, videos and screenshots

In which versions of MuseScore Studio is this issue present?

4.6.1

Regression

Yes, this used to work in a previous version of MuseScore 4.x

Operating system

macOS Sequoia 15.6.1

Additional context

No response

Checklist

• This report follows the guidelines for reporting bugs and issues
• I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible

Start by reproducing the issue in MuseScore 4.6.1 with a multi-page score, then compare the Header and Page Numbers text-style settings with a previous MuseScore 4.x version. Trace the handling of frames for these two page elements; done means a Header frame no longer affects Page Numbers and their frame settings work independently.