- Remove redundant `agent` re-declarations from trace subtypes
- Change TraceEventBase.type from `string` to literal union type
- Update onTrace callback type to `=> void | Promise<void>`
- Add readonly to onProgress/onTrace on OrchestratorConfig
- Remove Date.now() conditional guards (always capture timing)
- Auto-generate runId fallback when onTrace is set without runId
- Remove emitTrace from public API surface (keep generateRunId)
- Add TODO comments for runParallel()/runAny() trace forwarding
Add a lightweight onTrace callback to OrchestratorConfig that emits
structured span events for LLM calls, tool executions, task lifecycle,
and agent lifecycle. Zero overhead when not subscribed, zero new
dependencies.