_emit_progress_event strips legacy workstream_id from POST /progress/
payloads. Task and decision side-effect events now set workplan_id
explicitly so automatic progress logging stays workplan-first.
Legacy MCP tools and the workstreams resource now return _deprecation payloads
pointing to workplan-named replacements. get_domain_summary uses workplan-first
prose and exposes a workplans key alongside the legacy workstreams field.