release: 0.5.0 — get five merged accuracy fixes to the people installing today - #322

…ing today

Five fixes have been sitting on main since 0.4.0 this morning and none of them
reaches a user: PyPI still serves 0.4.0, which reads a tool the job merely named
as the cause of death. That is not a hypothetical — running `ci explain` over real
failing runs from public repositories put it at three of nine (httpx, prefect,
home-assistant) and then, on a second sweep across non-Python ecosystems, three of
seventeen (kafka, moby, opencv), where a `GRADLE_HOME=` line in a Windows
environment table was enough to diagnose a Java build failure in a job that never
compiled anything. A first-time user's first log is a real log, not a fixture.

Minor, not patch: `patchrail schema ci-classes` is new surface. The classifier
fixes are behaviour changes by design — a diagnosis that was wrong becomes right —
but no fixture changes classification or confidence (221 fixtures, top-1 1.0).

The GitHub Action's default range stays `<0.5.0` on purpose and is bumped
separately, once this is live on PyPI: 0.4.0 moved the `ci classes` JSON from v1 to
v2 in a minor bump and the break reached the Action silently, so the cap now earns
its keep. Verified before tagging: the Action's suite passes against a 0.5.0 wheel
and the payload it consumes is still `patchrail.ci_classes.v2`.