Removes the redundant open_workstreams mirror field from StateSummary (schema,
router, MCP get_domain_summary reader, dashboard consumers + empty-state stub,
and tests). Consumers already preferred open_workplans, so this is the
low-risk half of T04.
Deferred (still have live callers — not yet retirement-ready):
- workstream_id query/body field alias on preferred routes — external
session-close curls/scripts fleet-wide still send it.
- flows/workstream.yaml — /flows/workstream/{id} routes are still served and
exercised by tests; retire only once no callers remain.
Staged on branch state-wp-0070-legacy-retirement — do not merge until the 7th
documented zero-usage window is captured.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Replace the fixed 15s TTL on GET /state/summary with per-table revision
watermarks, stale-while-revalidate background refresh, and a progress-tail
section split. SQLAlchemy write hooks invalidate core or progress sections
on mutation. Adds tests, benchmark script, and operator docs.
