Instructions l.v. / l.v. sempre

Your idea

Most recently, a new feature "laissez vibrer" was introduced in MuseScore. This is a very cool thing, for which I express my great gratitude to the development team.
Only l.v. ties were introduced. I also raise the issue of the implementation of written instructions l.v. and l.v. sempre.

The l.v. instruction is equivalent to the l.v. tie/ties. It can be specified either independently (without l.v. ties) or in combination with l.v. ties (however, this is optional). Therefore, I suggest adding settings such as "show only l.v. instruction", "show "l.v. instruction and l.v. ties" and "show only l.v. ties" in the score style settings.
The l.v. instruction is usually not centered above the notehead, but is placed to the right of the note (most likely for better visual perception, since l.v. ties are also indicated to the right of the note).

The instruction l.v. sempre can be used to indicate that no notes in a passage should be damped. It is about passages. Here is an example:

Problem to be solved

Well, first of all, as I said at the beginning, only l.v. ties have been implemented in MuseScore Studio so far. Instructions such as l.v. or l.v. sempre could be a good alternative.
At the moment, the user can write these instructions as staff text. But this does not affect playback in any way. It's just a regular custom staff text. The user also has to manually shift the l.v. instruction to the right of the note. When editing the score, the layout undergoes many changes, including the width of the bars. Therefore, most likely the user will have to adjust the l.v. position more than once.
Take a look at the following example. Instead of adding an l.v. tie to each note of the passage, one could limit oneself to just the instruction l.v. sempre:

better than

laissez viber for glissando can only be designated using the l.v. instruction. This cannot be done with l.v. ties:

(to put it another way, how can you use l.v. ties to indicate that the played glissando of the harp should not be damped? The answer is no way)

As I already wrote in #21685, the only permission for natural sustaining resonance in musical notation is the instruction l.v. Otherwise, the instrument must be damped immediately, even without additional instructions for this.

Also, please note that in the case of the grand staff, the l.v. instruction must be centered between two staffs, like a dynamics. Often you also have to worry about this, because staff text cannot automatically center like a dynamics:

https://github.com/user-attachments/assets/22273d14-16de-44de-9390-8d0ca92bd2a3

Prior art

No response

Additional context

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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 the existing l.v. tie implementation and the related discussion in issue #21685. Define how standalone l.v. and l.v. sempre should affect playback, placement, grand-staff centering, and score-style display options. Done means the requested notation and playback behavior are implemented and covered by appropriate tests.