xlswriter 2.0.3

- Feature: autoSize(?string $range = null) sizes columns to fit their content. Column widths are estimated from the written cell values (wide/CJK code points count as two columns) and applied at output() time. Tracking is opt-in (call autoSize() before the writes it should size), so writes that never use it pay no per-cell cost; widths are clamped to Excel's 255 max (#305 / #514).
- Performance: worksheet metadata (merges, hyperlinks, protection, row/col options) is now loaded lazily instead of eagerly at openSheet(), so data-only reads (getSheetData / nextRow / nextCellCallback / putCSV) skip the second full XML pass — about 40% faster on large sheets.
- Performance: merge-follow lookups (SKIP_MERGED_FOLLOW) are indexed by last_row with a forward cursor, turning the per-cell scan from O(cells × merges) into amortised near-O(1).
- Fix: RichString leaked one zend_string per instance (the constructor's zend_string_copy was never released) and its fetch-object offset pointed at the wrong struct; both corrected.
- Fix: the cell/row-end/image/comment/chart callback bridges no longer zval_ptr_dtor an uninitialised return value when a callback throws or the call fails.
- Fix: xlsx_to_csv leaked its temp row on the write-failure path; openFile() now resets reader bookkeeping the way openSheet() and the dtor do; fileName()/constMemory() handle workbook/worksheet allocation failure instead of dereferencing NULL.
- Fix: the reader now reads every image from drawing.xml instead of stopping after the first 64 KB.
- Fix: PHP 8.6 compatibility — XtOffsetOf replaced with the standard offsetof, and zval_dtor with zval_ptr_dtor_nogc.
- Fix: setColumn()/setRow() leaked the per-call row/col options struct, and insertImage() leaked the path zend_string (#573).