fix(assistant): keep focus in the card, scope errors, guard links

From review of the canvas. Escape stopped working in three ways, each
leaving the keyboard grabbed with nothing to receive it: the history
field hiding took focus with it, a disabled input could not hold focus
while the daemon was down, and a click in a streaming reply focused text
the next flush destroyed. The card now gives focus back to the input
whenever it falls out, and the input is read-only rather than disabled.

Only an error the daemon marks as ending the reply (turn) closes the live
row; a command error, possibly another client's, used to freeze the reply
mid-stream. The running tool comes from state events, hello included.
Scrolling up during a stream no longer snaps back, since following stops
when a movement starts. History snippets go through Notify.sanitize like
any model output, links open only for http, https and mailto, and a line
opening with inline triple-backtick code is no longer taken as a fence.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions