Two bugs surfaced together while the model fired the todo tool:
1. Count flickered (e.g. 3 → 1 → 3) because tool.start echoed
args.todos as the live state. With merge=true (or any partial
replacement) args.todos is just the items being updated, not the
full list. Drop the early echo — tool.complete already carries the
canonical full list from the tool result.
2. After turn end the panel jumped from under the user prompt to below
thinking/tools because archiveDoneTodos() was pushed AFTER segments
in finalMessages. Prepend the archive trail msg so it sits right
after the user prompt — same visual slot the live panel occupied
during streaming.
c2ca02fcff