Generates sequential Indonesian letter/document numbers (nomor surat) from a preset or your own pattern. Placeholders: {seq} or {seq:N} for a zero-padded sequence, {unit} (bagian/divisi), {type} (jenis surat), {extra}, {monthRoman} (VIII), {month}, {year}, {yy}, {date} (YYYYMMDD), {day}. The date defaults to today; list subjects in the input to number each one, otherwise the count field decides. Output as a list, CSV or JSON. Everything runs locally.