An image send whose text+Enter RPC ended 'unknown' (ack loss / path
cutover) collapsed to accepted=true, so the terminal was never marked
stale. When the Enter truly never landed, the already-pasted image path
sat on the input line and glued onto the next plain-text message.
Propagate the send outcome through handleNativeChatSendWithOutcome and
mark the terminal input stale on any non-accepted outcome; the next send
heals with Ctrl+U (a no-op when the message did land). Chips still clear
on 'unknown' to avoid a double-send on retry.
e651fe91c6