[okewale667]

Summary

Implements #352 — machine-readable changelog for protocol behavior.

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What changed

src/changelog/protocol-changelog.service.ts

Added reload() with a rollback guarantee: if the incoming file fails validation the previous in-memory document is preserved and the error is re-thrown. A bad hot-swap cannot erase a working changelog.

src/changelog/protocol-changelog.service.spec.ts

Retry / reload path (4 new tests)

• Successful reload replaces the cache.
• Rollback on invalid file — previous document preserved.
• Rollback on missing file — previous document preserved.
• Recovery after a failed initial load once the path is corrected.

Authorization path (4 new tests)

• @Public() metadata is present on the controller class.
• StrategyAuthGuard grants access without a token.
• Empty query params returns 200 with no auth header.
• Impact filter works unauthenticated.

changelog/protocol-changes.json

• Machine-readable changelog entry references both issue Trellis API: Add machine-readable changelog for protocol-facing behavior #126 and Trellis: Create machine-readable changelog for protocol behavior #352.
• Migration notes document the reload() rollback guarantee.

docs/protocol-changelog.md (new)

Full operational runbook covering:

• Normal, failure, retry/reload, and authorization paths
• All 15 semantic validator rules with trigger conditions
• Edge cases: bad deploy, clock skew, CHANGELOG_PATH override, rollback procedure, contract preservation
• How to run the tests locally

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Acceptance criteria

Criterion	Status
Normal path covered	existing tests + service
Failure path covered	existing tests + 2 new rollback tests
Retry path covered	4 new reload() tests
Authorization path covered	4 new auth-path tests
Automated / executable verification	Jest specs + npm run changelog:validate
Operational edge cases documented	docs/protocol-changelog.md
Recovery / rollback documented	reload() rollback guarantee + runbook
Existing contracts preserved	no schema or API shape changes

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How to verify locally

npm run changelog:validate         # offline schema + semantic check
npx jest src/changelog --runInBand # all unit + integration specs

Closes #352

[preshotta]

Merged during the October maintenance pass after static malware-indicator review and a passing Malware guard. This is not a full security audit or a claim that the test suite passes. Please fix any remaining CI failures in a follow-up.