One public log. Nothing leaves it.
Every audit writes its entries, in order, into an append-only Merkle log: the commitment, each model call and its outcome, the result. Each entry is signed with a one-time hash-based key (LMS, RFC 8554). Every hour the worker signs a tree head covering everything so far.
Anyone can fetch the latest head and the public keys, and check that a receipt is included. Daily roots anchored on Solana come in Phase 2.
A receipt proves the audit ran as stated. It does not prove the code is safe.