should be peak picking a method of common-spectrum or method specific?

I started working a bit on the peak picking (https://github.com/kjappelbaum/xrd-analysis) but it seems to me that the code is not really dependent on the specific spectrum type (except for the peak shape). Maybe this should then be moved to common-spectrum?

What do you think @lpatiny ?

Start by reviewing the peak-picking work in the linked xrd-analysis repository and comparing it with common-spectrum. Determine whether the implementation depends on spectrum type beyond peak shape, then document or agree on the appropriate ownership before moving anything. Done means the method's placement has a clear decision and the affected behavior remains covered by the project's checks.

Written by the indexing model from the issue text.