[MU4 Issue] Regression: master tuning setting not implemented

[fredg999]

Describe the bug
The "master tuning" setting, which was located in the Synthesizer window in MuseScore 3, is not yet implemented in MuseScore 4.

To Reproduce
Steps to reproduce the behavior:

1. Open MuseScore 4.
2. Search everywhere for a master tuning setting.
3. Notice that you cannot find the setting.

Expected behavior
It should be possible to change the master tuning in MuseScore 4.

Screenshots
It's hard to show what's not there! ;)
See MuseScore 3's handbook to see how the setting was previously available: https://musescore.org/en/handbook/3/synthesizer#tuning

Platform information

• OS: Ubuntu 22.04.1 LTS, Arch.: x86_64, MuseScore version (64-bit): 4.0.0-223580304, revision: github-musescore-musescore-d759f29

Additional context
Since this issue probably needs design, I'd like to suggest that the master tuning setting should be a special text element to be found in the Pitch palette, and this for several reasons.

First, it would combine the communication of the master tuning to both people reading the score and MuseScore's playback system, in a similar way that tempo texts work. The text element could always be made invisible in case a user only wants the playback effect, but no text on the score (e.g. for standard orchestral scores with slight tuning adjustments, such as A4 = 442 Hz).

Second, it would provide the foundations required for the development of advanced features in the future. Here are a couple of examples:

• Change the master tuning over the course of a piece (e.g. Jacob Collier's cover of "In the Bleak Midwinter");
• Apply different master tunings to different instruments (e.g. scores for two pianos tuned a quarter tone apart) — this would imply being able to set the scope of the master tuning text, in a similar way that dynamics work;
• Choosing another reference note instead of the default A4 (e.g. scientific pitch defined as C4 = 256 Hz) — this would imply being able to recognize the pitch name in the text, in a similar way that tempo texts work;

By the way, a master tuning line akin to the accel. and rit. lines would be awesome (and I've seen some people request them on the forums), but I understand that's a relatively low-priority concern.

Scores saved with MuseScore 3 and earlier store the master tuning setting saved by the user, so I think it would be possible to recover this information when importing in MuseScore 4, and in that case a text element could be added at the beginning of the score. Again, that text can simply be made invisible for users who do not wish for it to be displayed on the score.

To sum up, I think text elements (and lines) for master tuning would be more intuitive and flexible for both beginners and advanced users, compared to setting it in the mixer or any other equivalent to the old Synthesizer window.

[DaffodilAura]

This indeed could be part of how MuseScore natively supports microtonality in the future. I'll have to add this information to my document...