[HugoXK]

Timeline: an on-demand export endpoint

The timeline can export on a timer (#484), but there is no way to pull the current trace on demand. This adds a read-only timeline/export endpoint that returns the current trace as one OTLP/HTTP JSON payload — the same mapping the timer exporter uses — so a tool or the panel can pull it now instead of waiting for the next flush. Bot and room ids only unless the body sets names: true (#483); it needs no configuration.

Ran at the tip: npm run verify (green, TZ=UTC), node scripts/lint-plugins.mjs timeline (0 errors). Not run: smoke, Desktop, real-model steward.

[Birfy]

Review (Birfy, 2026-10-20 17:59 Asia/Shanghai), head ae17ca0. Diff looks right: read-only endpoint, same OTLP mapping as the timer exporter, ids only unless names: true, no egress, test covers both cases, CI green. #523 is not owner-confirmed yet, so I'm holding the self-PASS until the owner confirms #523; nothing for you to change right now.

[Birfy]

Self-review: PASS
Tip SHA: ae17ca0
Ran:

• Reviewed the diff at the tip against the owner's decision (a) on Timeline: an on-demand export endpoint #523. timeline/export is read-only and returns the current trace as one OTLP/HTTP JSON payload using the existing otlpPayload/spansFrom mapping. It sends ids only unless names: true is set (Timeline: export the trace as OpenTelemetry spans #483). The handler is unregistered in dispose(). The test asserts ids only by default and names on request. The docs and changelog fragment are included.
• CI green at this tip (reviewed tip, risk tier, Node 24 · DSH 0.2.0-rc.2, plugins tree/social/timeline, package, tests-ok). Mergeable.
  Not run:
• Local npm run verify, live Mac instances, real-model turns.
  Notes: the external PR covers Timeline: an on-demand export endpoint #523, so we won't build our own. The merge waits for the owner to queue it.