**Plan ref:** Task 13, Milestone 5\n\nUpdate `docs/oauth.md` with oauth_grants opt-in. Add OAuth endpoints to `docs/api.md`. CHANGELOG entry under [Unreleased].\n\n**Files:** `docs/oauth.md`, `docs/api.md`, `CHANGELOG.md`
Plan ref: Task 13, Milestone 5\n\nUpdate
docs/oauth.mdwith oauth_grants opt-in. Add OAuth endpoints todocs/api.md. CHANGELOG entry under [Unreleased].\n\nFiles:docs/oauth.md,docs/api.md,CHANGELOG.md