A ReplyToolMixin UIWorker that grounds in the user's text selection (the
<selection> block in the snapshot) and points back via select_text — both
directions of deictic reference.
The voice LLM delegates to a ReplyToolMixin UIWorker that scrolls offscreen
items into view and highlights the phones it names — exercising the scroll_to /
highlight UI commands and the [offscreen] state tag.
Smallest UIWorker demo: a voice LLM in the main pipeline delegates
screen-relevant utterances to a UIWorker via a respond job; the UIWorker
auto-injects the current <ui_state> and answers grounded in what's on screen.
Includes a vanilla-JS client that streams accessibility snapshots over RTVI.
