Summary
Completes the tests/ unused-import cleanup deferred from the import-hygiene lint arc and widens both enforcement layers (CI ruff leg + L1 suite gate) to cover pact-plugin/tests/.
What landed
- CI import-hygiene leg 1 widened to
pact-plugin/(F401+F821); tests/-exclusion comment retired; F821 floor leg kept as deliberate structure. - 138 F401 findings resolved across 75 test files: 137 deletions (each cleared by a five-point AST-anchored whole-tree consumer scan) + 1 reasoned ensure-loaded keep with first-line noqa.
- L1 suite gate widened to sweep tests/, pinned by 4 counter-tests (self-inclusion reachability, subdirectory planted probe pinning glob recursion, strict-flip simulation, kept-seam noqa recognition).
- Review remediation: gate scope comment precision, sweep-recursion pin hardening, re-export probe noqa made first-line-visible.
Why
tests/ was excluded from F401 coverage only while it carried a known backlog. With the backlog at zero, both layers now enforce the same surface with the same first-line-noqa escape hatch — a future dead import in tests/ fails CI and the suite gate identically.