Squashed for a clean rebase onto develop (was 19 commits; the reviewer approved
the net diff at fb246080). Detaches an agent run from the HTTP request/browser
window: a run is a first-class lifecycle object (ai_chat_runs), a browser
disconnect no longer kills it, a concurrent-run insert-gate prevents double runs,
and a reopened chat live-follows a still-running run via a polled observer merge.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
agent_coder
68899a2c2e