Core dossier check: Send a CORS preflight OPTIONS request to https://<domain>/ and return the access-control-* response headers. Use to verify CORS policy for a specific origin-method pair, or to check whether a domain allows cross-origin requests; provide origin and method to simulate a precise preflight, or omit to use defaults (origin: https://domainposture.com, method: GET). Single OPTIONS request via fetch, 5 s timeout. Returns a CheckResult: on success, {status:"ok", headers:{access-control-allow-origin,...}}; on failure, {status:"error", reason}.
ConnectorNo auth