Add support for Selective Damp (Handbells/Handchimes)

Your idea

In handbell and handchime notation, during an "LV" section, a damp symbol on the stem of a cue note indicates that those notes should be damped. A damp symbol on the stem of a regular note indicates that those notes should be rung normally and then damped at the end of their normal duration. MuseScore should add support for this notation, as well as implementing playback support.

When a stem spans across staves, the selective damp symbol should be placed between the staves (see "Example 16" illustration below). Otherwise, the selective damp symbol should be placed between the note head and the end of the stem, and should automatically move with the stem when "x" is pressed to flip the stem direction (see "Example 17" illustration below).

If a note of the same pitch (and the same instrument, i.e. handbells vs. handchimes) was already ringing and sustained because of an LV, the sustain should stop when a selective damp is encountered, and (for regular non-cue notes) the damped note should be rung normally without sustain. Subsequent notes within the same LV section should be sustained.

I suppose Selective Damp symbols should probably have a Play checkbox, which if unchecked should cause them not to damp sustained notes?

It is not clear to me exactly how the UI for the cue notes version of this should work. These aren't normal cue notes; these would behave more like grace notes, which are inserted before a note or rest, with no duration of their own, and should always have the appearance of small quarter notes. Any ideas?

Problem to be solved

Currently there is no support for this notation (other than manually positioning the damp symbol over a stem), nor is there a way to get playback to work.

Prior art

No response

Additional context

From AGEHR's Handbell & Handchime Notation guide:

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

The issue names no files, tests, or entry points. Start by studying the existing handbell damp and LV notation behavior, then review the supplied AGEHR examples and related playback behavior. Done means selective damp symbols support stem placement and flipping, cue-note behavior is defined, and sustained notes play back correctly.