The product is promoted in the one repository, on every land

GitHub is the only repository (“github should be the only repo”, the user, 2026-10-21; the design is the coordination notes’ specs/github-only.md, §2.2 and §9.4). The product stops being a second repository and its master branch. It is the product branch of the one repository, a projection of main computed by the profile promotion/main-to-product.json:

• main changes only through pull requests and the merge queue, so the local push hook no longer starts a promotion. The profile’s trigger is manual. The trusted publish workflow promotes after every land, as the publisher App: a signed commit through the Git Data API, with parents [product, main], a Projected-From trailer and a projection attestation. This supersedes PROMO-AUTO.
• Nobody edits or merges into product; the ruleset lets only the publisher write it, which is UR-12 on GitHub.
• The first promotion onto product is reviewed, as PROMO-FIRST’s was. The branch is seeded from the archived product repository’s history, so that promotion accepts the plan’s exact target edits and deletions with a reason. Every later promotion is unattended.
• Releases are the release train’s (harness release), tagged on product.

Pending until the publisher lands (lane GH-5): until then, nothing promotes.