spec: bind signature mode to the signer allowlist in the normative text

[MongLong0214]

The normative spec describes a weaker gate than the implementation enforces

#642 (#597) made signature mode require two things: Git's G status and an exact %GF fingerprint in the repository-local commitlore.trustedSigner allowlist. Every user-facing surface picked that up. The normative text did not.

Surface	Carries the allowlist requirement
README.md, README.ko.md, README.ja.md, README.zh-CN.md	yes
docs/cli.md (lines 29–31, 143)	yes
docs/capture.md (line 150)	yes
docs/adr/ADR-0005-trust-minimal.md	yes
spec/SPEC.md §7	no — still G status only

Why this is worth a PR rather than a follow-up note

SPEC is what an independent implementer reads; the README is not. Building to §7 as written produces a verifier that grades a record [directive] where CommitLore grades it [claim] — a signed commit from a key in Git's trust store but absent from the repository's allowlist.

That is the same class of defect as #631, where one record graded differently through the CLI and through MCP. Here the divergence is between the spec and the implementation rather than between two routes, and it is the more durable of the two: a runtime skew is fixed by converging runtimes, while a spec that understates a security condition keeps producing under-built verifiers for as long as it stands.

What changed

Two sentences in §7. The wording is transcribed from ADR-0005, which is already merged — this carries no new decision, and the missing pieces are the ones that change behaviour:

• the %GF fingerprint must appear in commitlore.trustedSigner;
• an absent, empty, or unreadable allowlist authorizes nobody, so every record renders as a claim — it never means every valid signer is authorized;
• a verified signature establishes that an accepted key signed the commit, while the allowlist is what supplies repository authority.

The closing "minimum, not a solution" sentence now names the allowlist alongside Git's trust store.

Verification

bash spec/verify.sh                    OK: 32 fixtures + README example sync + vocab table
node scripts/check-readme-numbers.mjs  block matches bench/report.ts

§3 is untouched, so the README↔SPEC vocabulary check is unaffected.

Raised as a PR rather than pushed, since §7 is the CTO's contract surface — if the intended reading differs from ADR-0005's, the ADR is the text to reconcile against.

[github-actions]

CommitLore — record lint

Trailers: clean — 1 commit in origin/main..feaf59a4e5bd773d79b24b48d37f7693f35768fb
Active constraints: not read — commitlore: the index is incomplete: the build stopped after its time budget with 532 commit(s) or note(s) unread — records in them are missing from this answer. fix: commitlore init (or commitlore index) to finish the index (1 changed path)

_{Trailer violations fail this check. Active constraints are informational — they are what the repository already decided, not a verdict on this PR.}