Edit a fiber production process

Replaces name, productCategoryId, facilityProcessId and facilityWastageFactorPercentage (all required; 0 to 99.99) of a production process the caller's company owns. featuredImageFileId left out keeps the stored image and null clears it; legacy cleared it whenever the key was absent. The wastage band is re-read for the category and facility process, falling back to the category's parent: a wastage below its minimum answers 409 invalid_wastage_factor, a changed pair without a production factor 400 missing_production_factor, and an unchanged pair whose factor is gone keeps its stored band (legacy wiped it). The facility process is now stored (legacy dropped it). Responds with the process in the { data, metadata } envelope (legacy answered the bare record). 404 not_found for an unknown id or another company's process (legacy answered 500 for another company's).