Three seams: the offer is known when the wait starts (a confirm and a question,
with and without the platform capability), a button pressed after the
notification appears answers the tool confirm it belongs to — a pty stands in
for the terminal so the read has to consult both surfaces — and `confirm()`
takes an answer passed in and one offered by the wait hook, without asking the
backend.
A prompt that has waited `grace_seconds` is now announced, and where the
platform allows it the notification carries the answer: allow / deny / review
for a confirmation, a reply field for an `ask_user_*` question. Picking
"review" withdraws the notification and keeps waiting at the terminal, and a
notification is dismissed as soon as the prompt returns — answered or not.
Two channels. The desktop one is the optional `notify` extra, run on its own
event loop in a daemon thread because a notification's callbacks only fire
while the loop that owns it is running (the library's synchronous wrapper does
not provide that). The terminal one needs nothing: it writes OSC 777 / OSC 9
to `/dev/tty` — so a redirect cannot swallow it — picking the protocol from the
environment and wrapping it for tmux / screen, falling back to a plain bell.
kitty speaks OSC 99 only, which is not implemented, so it keeps the bell.
Nothing here can break a prompt: a missing extra, a desktop that refuses, a
failed write all fall through to the next channel and never raise. Titles are
flattened and stripped of control characters, and the reason line (which can
name a command or a URL) only travels with `include_reason`.
NCBM