ReviewBench Harbor runtime 0.1.0rc1

Experimental generic Python runtime from PR #51. Install alongside Harbor 0.24.0 pinned to b53b8134e1241686dca7759af188f987ecc48e8b. Provides reviewbench_harbor.reviewbench_plugin:ReviewBenchPlugin, reviewbench-check-job, and reviewbench-check-dataset. Consumers need no ReviewBench checkout or host-side Node/npm. Includes no vendor adapter, private profile, credentials, or paid execution. Verify the wheel with SHA256SUMS. See docs/HARBOR.md at this release tag for direct Harbor usage.