CultPayloadDepth.Check walks MessagePack headers iteratively and refuses the first
container past CultMessagePackSecurity.MaximumPayloadDepth, read or skipped, called by
SerializeUntyped (on the bytes it produced) and DeserializeUntyped (before decoding).
UntrustedData's 500 is replaced by the same value as a backstop. CultUnionGuard refuses
[k, nil] arms. New vectors in tests/vectors/union-parity, with bounds-outcomes.msgpack
as their data; the gate now runs every Check-calling test body and fingerprints bytes
and write times. All commits build.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
abf624ab04