Collapse the repeated signature-length checks, delegation-signature counting, JSON-based signer equality, and per-index signing loops into shared helpers within each package.

Two of the deduplicated call sites, the program signers in makeLogicSig and Ed25519AppendMultisigToLogicSig, previously copied the raw signature without checking its length, silently accepting a short signature from a custom Ed25519Signer as a subsig. They now return errInvalidSignatureReturned like every other signing path.

Move the PQ golden tests to the transaction package so they exercise PQAccountTransactionSigner directly, and drop signPQAccountTransactionFixture, a test-only reimplementation of the signing envelope that could have passed while the real signer was broken. Add coverage for the rekeyed PQ signer.

ROADMAP.md and AUDIT_READINESS.md both named NLnet NGI Zero -> Radically Open
Security as the primary path to an independent security audit. NLnet's director
declined in writing on 2026-06-29: the NGI Zero programmes have ended and no
audit funding is available. Both documents were written 2026-06-03 and never
updated -- 67 days of a stale claim about the audit path, one of them sitting in
the audit-readiness document itself, which is the first file an external auditor
reads.

The honest state: the audit is a paid engagement, not yet funded, or a grant not
yet identified. That is a worse position than the documents described, and it is
the one a reviewer needs to see.

Found while triaging 64 Gmail drafts: the unsent 2026-07-04 draft to bob@nlnet.nl
was a two-line courtesy acknowledgement of the decline, not a live request.

Security impact: documentation only. Weakens a claim rather than making one.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>