Count records

Count of one Corpus's authorized Records. Time-bounded counts are exact within a two-second query budget; larger windows return non-retryable 422 record_count_too_broad and require narrower bounds. Unbounded counts probe at most 10001 identities: up to 10000 are exact, larger Corpora return stored catalog totals with approximate=true. complete=false means initialization has not finished; incomplete zeros must not be presented as empty. observed_at names the independent read snapshot. Includes withdrawn Records, as the listing does. Records without a current Version are counted only when neither bound is supplied. Uses content:read and the same Corpus scope as listRecords. This is an independent read, not a snapshot shared with listing pages. Equal bounds count zero; reversed bounds, malformed dates, duplicate or unknown parameters return 422 invalid_query.