remote.focus lets a controller keyboard-capture lease ask core to enter
or leave remote focus; the reply acknowledges admission only. Core
reports the actual state with remote.focus events and forwards routed
transitions as remote.input events carrying the source keycode and, on
fresh presses, a canonical key name. A full focus mailbox revokes the
lease; revocation drains pending focus work. No native capture owner is
attached yet.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>