Complete MCP legacy deprecation coverage (resource + docstrings + TOOLS.md). Dual-write open_workplans on /state/summary alongside open_workstreams; get_domain_summary prefers the new key. T06 internal rename started.
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.
