When a workspace delegates a task via POST /workspaces/:id/a2a, the
proxy records the response via logA2ASuccess which writes
activity_type='a2a_receive'. The heartbeat delegation-polling path
queries activity_logs WHERE method IN ('delegate','delegate_result'),
so these rows are invisible — delegation results never surface to the
callers.
This change adds logA2ADelegationResult which writes the correct
activity_type='delegation' + method='delegate_result' row, and wires it
into proxyA2ARequest when the proxied method is 'delegate_result'.
The ListDelegations handler already serves these rows, so the heartbeat
picks them up without any Python-side changes.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
