The × button added for the mobile workspace panel close in v0.47.0
had a title= attribute but no aria-label. Screen readers may announce
the raw × character ('times' or 'multiplication sign') instead of
reading the title. Added aria-label='Close workspace panel' to match
the accessibility pattern used by other icon buttons in the panel header.
All 645 tests pass.
Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>
068836cf6b