provenance is two fields, superseding the three origin classes

AGENTS.md carried both schemes at once, so the repository did not have a provenance scheme; it had two. Resolved to generator plus review status.

The three-class scheme cannot express the case this repository is built for: an external contribution is neither human in the sense meant (a maintainer wrote it) nor llm-reviewed (nobody reviewed it), and calling it llm-unreviewed asserts a generator nobody knows. Who made a thing and whether anyone vouches for it are independent, and one label cannot carry both.

ci-only replaces llm-unreviewed as the ordinary honest state. Dependent references were updated in PROVENANCE.md, CONTRIBUTING.md, README.md and the pull-request template. Completed round reports keep the vocabulary that was true when they were written; no script parsed the class names.