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>

1 files changed, 5 insertions, 0 deletions

diff --git a/desktop/assistant/README.md b/desktop/assistant/README.md
index 0f80993..8fc200b 100644
--- a/desktop/assistant/README.md
+++ b/desktop/assistant/README.md
@@ -40,6 +40,11 @@ Notes:
   `ServerNotFoundError` warning each time.
 - **`tools` is a comma-joined string role.** A ListModel role holding an
   array becomes a nested model, which `setProperty` cannot append to.
+- **A stopped reply is shown, not kept.** The daemon does not save a
+  partial turn, so it is gone after the next reopen or restart.
+- **Only an error marked `turn` ends a reply.** Every client sees every
+  event, so a command error (another canvas opening a deleted
+  conversation) shows above the input instead.
 - **Search snippets** mark matches with `**`, rendered as bold; backticks
   are stripped first, since a match inside a code span would show the
   markers literally.