After the release-ready refactor in 11837ed the unassigned/active
split runs in Python on `all_active_wos`, so the old SQL domains
(`domain_unassigned`, `domain_active`) no longer exist — but the KPI
block still referenced them via `MrpWO.search_count(domain_unassigned)`.
Manager page crashed with `name 'domain_unassigned' is not defined`.
Fix: derive the KPIs from the in-memory recordsets we just split, no
re-query. Also documents why we can't SQL-count: x_fc_is_release_ready
is a non-stored compute, so search_count would silently miss the
release-ready predicate.
8fc864623b