Ability to see/interact with permanently hidden instruments/staves in continuous view

Your idea

I'd like to be able to see/interact with staves that are marked hidden in the instruments panel, preferably in continuous view.

Problem to be solved

If a staff is hidden for a particular system because of "hide empty staves" settings, you can always switch to continuous view to access it. But if a staff/instrument is hidden for the whole score, there's no way to interact with it at all other than unhiding it again (which can cause considerable delay causing re-layout and result in material moving around disconcertingly in Page View). If you're in Continuous View, the ability to have hidden staves shown like other hidden elements (using the default "grey" colour) would make interacting with such staves much simpler, when using them for playback workarounds in particular.

Prior art

Encore always shows all staves in "Linear View" (equivalent of Continuous View).

Additional context

Obviously in the ideal world you'd never need hidden instruments or staves in order to facilitate playback etc. but there are various reasons it's likely to be quite a while that it is needed (e.g. I've used it because I have arco & pizz combined on the same staff, which MuseScore doesn't support for playback, so the pizz. notes for playback are in a hidden stave).

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

No source files, tests, or entry points are named. Start by locating continuous-view rendering and the logic that excludes instruments or staves hidden for the whole score; done means those staves can be shown and interacted with in continuous view without unhiding them or triggering page-view re-layout.