Zero padding number generator

Only plain integers (with an optional sign) get padded, because leading zeros only make sense for whole ids. Decimals, hex, and words pass through untouched or flagged, and a number past the width comes out exactly as it went in. The split runs on newlines and commas, so a thousands-style entry like 1,234 reads as the two tokens 1 and 234; strip commas first if your list uses them as digit separators.