Request: Add Bayan Accordion Input Method.

Your idea

Introduction:
I propose adding a bayan accordion input method to MuseScore, which would enhance the software's usability for musicians who play this instrument.

Description:
(edited) I'm sorry that I only need an input method. There is no need for any special "notation system" of bayan, because that does not exist. The standard 5-line staff system just works.
It is not about specific engraving/score layout features.

Use Cases:

• Use the whole keyboard instead of only the seven keys A, B, C, D, E, F and G to input the notes beyond an octet.

Implementation Ideas:
One possible implementation approach is to create a specialized input method that allows users to input bayan accordion notation through a user-friendly interface.

Examples:

Related Work:
http://benzguo.github.io/bayan/
https://xantorohara.github.io/xenoharmonica/

Proposed Timeline:
I hope to see this feature integrated into MuseScore within the next 6-12 months, pending community feedback and developer availability.

Request for Feedback:
I invite the MuseScore community to provide feedback on this proposal. Your input and suggestions are highly valuable in shaping this feature request.

Conclusion:
Adding support for the bayan accordion input method would greatly benefit MuseScore and its user base. I look forward to working with the community to make this feature a reality.

Problem to be solved

The input of note by the keyboard is too difficult, especially the "C3-G3-E4-G3" Clayderman's decimal arpeggio.
By using the input method of bayan accordion, it will be easier to input. Using the whole keyboard, at least 26 different notes can be typed at once without moving the input range.
Also as mentioned above, we know that there are 88 keys in a piano, so the input method can set the input range of which notes will be typed.

Prior art

No response

Additional context

No response

No files, tests, or entry points are named in the issue. Begin by turning the requested keyboard mapping, octave range, and acceptance behavior into a concrete scope; done would require an agreed design and an implemented input method validated for the stated use cases.