Bounded digest failures without body, field, or algorithm input bytes.

:mismatch means a computed checksum differs. :unsupported_algorithm means no SHA-256/SHA-512 checksum can be checked, or computation requested another algorithm. :uncomputed_algorithm means a stream did not hash a supported algorithm present in the field. :conflicting_digest rejects a supported algorithm repeated across combined field occurrences, including identical checksums. :invalid_digest_length rejects a known algorithm's wrong checksum size. :invalid_preference rejects a weight outside 0..10. :body_unavailable distinguishes missing/consumed/streaming bytes from retained empty content; :representation_required requires explicit complete representation bytes. :invalid_field rejects a selector other than the two RFC 9530 preference field names. :invalid_body, :invalid_message, :invalid_kind, :invalid_chunk, :invalid_state, and :invalid_options reject invalid caller values. A :max_bytes above 16 MiB on compute/3 or check/3 returns :invalid_options. :limit rejects excess content bytes. Structured Fields errors retain their own bounded reason vocabulary. No failure returns partial integrity facts.