Detach websites

Removes an explicit selection of website associations from the configuration; the twin of \"Sync websites\". Answers **200** the same way: `meta.status`, `meta.updated` and `meta.skipped`.\n\n**Body** (JSON):\n- `sites` (array of website ids, required, 1 to 50), validated for existence only.\n\nA website not associated, or outside the token's reach, is answered in `meta.skipped` with a `reason_code` (`ALREADY_APPLIED` meaning \"not associated\" here, `PERMISSION_DENIED`) and a message. A restricted member reaches only their own websites: an association outside their reach survives the call untouched.\n\nRequires a full-access token (read-only tokens answer 403). Body validation runs before authorization: a foreign configuration with an invalid body (e.g. missing `sites`) answers 422; only a foreign configuration with a valid body answers 404.