v1.5.1 counted gate-28 as APPLICABLE whenever `lib/` existed and
composer.json declared a license, regardless of whether the PR touched a
single PHP file. A PR that changes only a workflow, a lockfile, a spec or an
info.xml therefore fails on:

  [gate-28] license-triangle: SKIPPED (structural) — ... 0 in-scope
  lib/**/*.php file carried an @license ... so NOTHING was compared

with `hydra-gates-require-full-coverage` on, which is now the default. The
gate was right that it compared nothing; it was wrong about why. Nothing was
in scope, which is ADR-020's diff-scoping doing its job, and that is exactly
what the NOT-APPLICABLE classification exists to say.

Tagged because the fix has been sitting on main untagged, and every consumer
pins a tag — an untagged fix reaches nobody. Observed on openregister#2365,
whose diff is info.xml + package.json + a lockfile + one spec.