Add wave autopositioning for N163 instruments in instrument editor

FamiTracker Beta v0.5.0 had the ability to autoposition the wave position via a dedicated checkbox, but this feature is not present in Dn-FamiTracker and I would like that added in v0.5.3.

An example of that feature is in the image below:
<img width="586" height="420" alt="Image" src="https://github.com/user-attachments/assets/0c3fde97-56da-4962-baa7-3302039717cc" />