The Cmd/Ctrl+/ predicate keyed off e.code==='Slash' + !e.shiftKey, which on
QWERTZ layouts (a) stole Ctrl/Cmd+- browser zoom-out (physical Slash there is
the minus/zoom key) and (b) missed the real shifted-'/' chord. Match e.key==='/'
instead — layout-correct on every keyboard. Tests updated to assert the physical
code isn't used and a layout-shifted '/' still matches.
Co-authored-by: nesquena-hermes <agent@nesquena-hermes>