Pull request #1825: PIPE-2947: Improve `_savgol_filter_nan` to pad NaNs around masked regions
Merge in PIPE/pipeline from PIPE-2947-savgol-filter-nan-version2 to main
* commit '1364dd8064999cc14aa5c71df7c178e6dc5928a2': PIPE-2947: Make `_savgol_filter_nan` signature compatible with `savgol_filter` PIPE-2947: Improve _savgol_filter_nan to pad NaNs around masked regions
PIPE-2947: Make `_savgol_filter_nan` signature compatible with `savgol_filter`
Promote `polyorder` from **kwargs to an explicit parameter, matching
savgol_filter's positional signature. Update call site keyword order
to reflect the new signature.
