cellsynth 0.1.0

• First release. Cell-wise rolling censor-and-redraw synthesis with CART leaf donors (raw strings copied), synthesised missingness, cell and row censor modes, lock groups for coupled columns, auxiliary predictors from other tables.
• Every sheet of a workbook is synthesised into one output workbook; empty and small sheets are copied, blanked or dropped (small_sheets).
• Identifier detection covers CDISC/EDC key names (USUBJID, SUBJID, SITEID, …), multi-segment and zero-padded codes; identifiers and text columns can also be named or matched by pattern (id, id_pattern, text, text_pattern, or session-wide via options(cellsynth.id = ...)).
• Very wide sheets (9,000+ columns) are screened block-wise in bounded memory.