fix(newos4): chat() threw on every tool-using turn and never returned its answer

Regression from 32608bc, caught by the .chat() caller sweep before it aged:

- `recent` was referenced in chat()'s finally block but never declared, so any
  turn with toolTurns > 0 threw ReferenceError there and chat() REJECTED.
  delegateTask's catch turned that into "agent failed"; the 'completed'
  fallback was only ever reachable on tool-free turns.
- chat() still had no return at all, so a tool-free turn resolved undefined and
  module-orchestrator.js:1250 fell through to `|| 'completed'`.

Both fixed: `const recent` is now built from _toolCallLog, and chat() returns
{ content: finalAnswer, toolTurns } before the archive block (a return at the
end of the method would let _archiveSession swallow the answer).

Verified with /tmp/probe-chat-hotfix.js, 6/6: tool-using turn resolves
{content:'WORKER ANSWER', toolTurns:2}, tool-free turn resolves the answer,
the orchestrator's own projection returns the answer instead of 'completed',
and _chatLock is released. Run against 32608bc the same probe says
"recent is not defined" - i.e. it reproduces the shipped defect.

Not included: the _chatLock serialisation (orchestrate-parallel still runs
sub-tasks one at a time and the 10s force-release can clear the main turn's
lock). That stays open in STEER-20261102-201045-ab08.

0 files changed, 0 insertions, 0 deletions