Resolves issue #1882, Prevent append-audit requests without history from returning a 500.

[david-rocca]

Closes Issue #1882

Summary

Append-audit requests now validate history before iterating it. Requests without a valid, non-empty history array return a clear 400 validation error instead of throwing a TypeError.

Important Changes

src/controller/audit.controller/audit.controller.js

• Added append-audit validation for missing, non-array, or empty history.
• Returns MISSING_REQUIRED_FIELD before opening a session or iterating entries.

test/integration-tests/audit/auditTest.js

• Added a regression test for append-audit requests without history.
• Retained existing success-path coverage for valid append-audit requests.