ADR-0087 exemption (no-migration-prescription): The retired arm has no metadata surface for `objectstack migrate meta` to reach: `binding` is not a `packages/spec` key, has no Zod schema and no stored `sys_metadata` representation — it is a member of three published TypeScript interfaces in `packages/sdui-parser`, delivered to the only affected party (a TypeScript consumer) by the compiler at their own call site. There is consequently no stored shape to rewrite and no prescription to ship, which the body states rather than omits: the arm has zero writers in this repository (firing `binding: 'object'` control = 2), zero `binding` keys of any spelling in the tracked `sdui.manifest.json` (339 inputs), and zero readers outside the package.