Blank cell and row repeats that run past 16384 columns / 1048576 rows
(padding from writers with larger sheets) are clipped instead of
rejecting the file; any data or merge past the edge is still an error.
convert() builds its Cell with ..Cell::value(value) so new Cell fields
take their defaults.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Resolves the shared integration points for both formats: combined sniff,
file.open spec, file filters, MCP description, docs. open_bytes now lets
sniffed content (ODS or XLSB) win over the extension.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>