The functional/playwright split is purely organizational (discovery globs both
with no branching; same custom tier -> L4 rung, same fixtures, same failure
semantics). Migrate all custom tests to one custom/ folder; M1 proves coverage
identical before/after (no silent drops), M2 is a full real-CI !testme sweep
across all recipes confirming levels unchanged. cfold becomes the last phase so
the queued /upgrade-all fires after it (folder change verified before upgrade).
