docs(delegation,api): document stall detection, timeout metadata, /agents live status, runs-stream subagent lifecycle
Catch the docs up to this week's delegation work:
- delegation.md: structured timeout metadata fields (timeout_seconds/
timed_out_after_seconds/timeout_phase, #72403); new 'Stall Detection
for Background Subagents' section (progress-based monitor, thresholds,
grace window, stalled event metadata, root-cause fix note — #72227/
#72300/#72412); /agents per-child live activity on CLI + gateway;
all-thread diagnostic dump note.
- api-server.md: /v1/runs events stream now documents subagent.start/
subagent.complete forwarding, redaction, child_session_id, and the
deliberate exclusion of per-tool child events (#72406).
- sidebars.ts: register the subagent-lifecycle-api developer guide page
(shipped in #72501 but absent from the sidebar).
Docusaurus build verified.
4b4d2ae4cd