PASS baseline evaluates cleanly -> qualified
PASS exception fault -> error
PASS non-boolean result (None) -> error
PASS non-boolean result (1 == True) -> error
PASS evaluated False (the ONLY skip) -> unqualified
PASS evaluated True -> qualified
PASS sibling-prefix shadow path -> error
PASS preloaded foreign module -> error
PASS mutation baseline: gates clean on the real carriers
PASS mutation: corrupted matrix row -> gate FAILS
PASS mutation: deleted header dependency -> gate FAILS
PASS mutation: retired formulation reintroduced -> gate FAILS
verifier fault matrix: 12 classifications hold — no fault becomes a successful skip; gate mutations FAIL
