Helper to extract a p-value from a coefficient table returned by
RTransferEntropy or similar packages. It searches for a column whose
name matches "^p[._ -]?value$" (case-insensitive) and returns
the first-row entry of that column.
.get_pval(obj)A numeric scalar with the extracted p-value, or
NA_real_ if no suitable column is found or extraction fails.
An object for which coef(obj) returns a matrix
containing a p-value column.