records(packet): verify the pin timeline for recorded acts

[TusanHomichi]

A canonical, rehashed trainee packet could attribute a signoff to a program version pinned only later, or place phase activity outside its named pin epoch. Verification now checks when the claimed version was pinned and reports DocumentPinHistory for temporal contradictions.

• Retain each epoch's opening and closing instants. Signoffs must name a version pinned at signed_at; phase effective/recorded instants must obey their explicit epoch boundaries. Reject version-change timestamps that reverse recorded order.
• Keep boundary seconds inclusive: changes and acts within one Unix second cannot be ordered across tables. Preserve intermediate pins during multiple same-second changes and distinguish separate visits to an earlier version.
• Add ADR 0017 and update normative check 8. The producer already carries the required fields, so packet format version 1 and stored bytes remain unchanged.
• Move pin-history tests into tests/trainee_packet/pin_history.rs, with shared fixtures/helpers retained by the parent. No public or persisted impact from the test reorganization. Add canonical, rehashed forgeries, exact boundary cases, revisited versions, and a round trip through domain services and the real exporter.

Validation at 051a10e: npm ci, npm run check, npm run build; cargo fmt --check; cargo clippy --workspace --all-targets -- -D warnings; all 130 workspace Rust tests; explicit debug binary build; and all eight browser tests (npm run e2e -- --workers=2 --trace retain-on-failure, 30.0 seconds) pass. Heavy local suites ran sequentially. The web install reports the three existing low-severity npm audit entries tracked in #54.

The verifier checks consistency with the supplied history and fingerprints. It cannot establish provenance or resolve unstored subsecond ordering; a backwards clock that produces contradictory change timestamps is reported rather than silently reordered. No preview deployment is included.

Closes #52.

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-05T00:17:00.243091Z	051a10e	Draft marked ready

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