The diff is a three-line engine change: it adds the string "history.yaml" to the enum of pin-checkable files in both branches of PinCheckSchema and to the loader's list of files read into checkableFiles. No content records, citations, locators, assessments, or provenance fields are touched, and the citation tooling found no identifiers to check. AGENTS.md is untouched. Directionally this widens what the fail-closed pin machinery can guard rather than narrowing or bypassing it, so §3.15's prohibition on weakening the checks is not engaged; pins still bind presentation only, and history.yaml remains an append-only changelog (§3.14). The PR body's references to a 'downstream metabolism sync' and a falsification incident are unverifiable from here but are motivation, not normative claims embedded in published content, and nothing in the diff depends on them. Ordinary, in-scope engine work.

The change only extends the list of files that pins can guard and that are loaded as checkable content by adding `history.yaml` alongside existing content files. This strengthens provenance and change-history protection, aligning with §3.14’s requirement that important changes and assessments be versioned and inspectable. It does not alter any existing assessments, remove provenance, or weaken verification or ratification checks under §3.15; the pin system remains append-only and enforced. No citations or locators are introduced, so rules about fabrication, exact provenance, or citation verification are not implicated. There are no edits to AGENTS.md or other constitutional text. Overall, the modification tightens rather than relaxes epistemic safeguards around change history.

The change cleanly extends the `PinCheckSchema` and file loader to support `history.yaml`, allowing the system's pin checks to evaluate the case changelog. This adheres to §7's mandate for build-time enforcement of pinned commitments and supports §3.14's emphasis on versioning. The code additions are purely mechanical schema updates that do not weaken any checks (§3.15) or violate epistemic rules.

The diff only adds history.yaml to the pin-checkable file lists in PinCheckSchema (both check kinds) and to loadCase's checkableFiles read list. That extends fail-closed pin enforcement to the append-only changelog so banked strings can be required to remain present, which matches §7 (pins.yaml commitments, banked corrections, presentation not verdicts) and does not weaken §3.15 checks. AGENTS.md is untouched; no content, citations, assessments, or provenance records are added or rewritten. Omitted-files is empty and citation verification found nothing to resolve. Ordinary engine extension, not a constitutional break.

The diff is a three-line engine extension: it adds 'history.yaml' to the loader's checkable-files list and to the two file enums in PinCheckSchema, letting the fail-closed pins mechanism guard the append-only changelog. This strengthens rather than weakens the constitution's checks (§3.15's prohibition on weakening checks is not engaged; if anything it extends enforcement of §3.14's version-everything requirement by letting banked corrections in history.yaml be pinned against silent removal). AGENTS.md is untouched, so the human-only amendment reservation is not triggered. No citations, sources, assessments, or provenance are added, so the real-citations and provenance rules have nothing to bite on, and the citation verifier found no identifiers. The omitted-files list is empty, so the diff is complete. The PR body's references to a 'downstream deployment' incident and 'metabolism sync' are untrusted context I cannot verify, but the compliance question turns on the diff itself, which is a small, coherent, check-expanding change consistent with §7's pins design (pins bind presentation, never verdicts).