Composer::row uses ColumnWidths::parse; rowWidthsError and its error-state
save/restore are gone. The update width check moves out of
DiviUpdateAbility into ColumnWidths::updateErrors. Behaviour unchanged.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7
