Read one owned SWEEP person through the safe field allowlist.

The read is quota-neutral and requires bernayser:read. Unknown and foreign identifiers share not_found, preserving owner cloaking, and a dark surface uses the same response. No profile, confirmation JSON, user_id, token, or URL can appear. Recover from scope_missing with an explicitly minted catalog key; retry rate_limited or service_unavailable only after retry_after_sec. Requires the explicitly minted bernayser:read scope; bernayser:read permits safe projections and bernayser:write permits mutations. This BERNAYSER operation is quota-neutral. While dark it returns not_found, and a valid key without the required scope receives scope_missing. Fix a non-retryable request or credential before retrying; for rate_limited or service_unavailable, wait for retry_after_sec and retry once.