[RefImpl] Read the trace exporter's names from the mapping, and close its test gaps #284

Target runtime or language

AGT reference Guardian: packages/guardian/src/otel-trace-exporter.ts, audit-to-otlp.ts, and their tests

What this proves

This is part of issue #274, the third of three slices.

PR #275 has merged, so the exporter and the converter can now read their names from otel-mapping.json. This slice also closes test gaps, so a wrong attribute or a wrong path fails a test.

Scope:

1. Read the failure event name and step_span_attributes from the mapping, and delete the comments that say the mapping lacks them (otel-trace-exporter.ts, around line 111).
2. Delete DECISION_DETAIL_NAMES, because the mapping now covers those names.
3. Take the FailureClass list from the mapping. It has 8 classes, including signature_invalid and handshake_failure.
4. Converter input checks:
   • Treat failure kinds as plain keys, so a kind named like a prototype property (toString, for example) does not match.
   • Clamp oversized error codes.
5. The converter reads seq. It reports gaps, duplicates, and recorded_at going backwards, and it exits non-zero. A deleted line must not disappear without a report.
6. Tests:
   • the "empty array is absent" rule;
   • make the off-by-default test able to fail (otel-trace-exporter.test.ts, around line 1045);
   • an end-to-end join test across the Guardian and converter files;
   • the converter's posture and parsing paths;
   • give the slow converter test (about 19 s locally) a timeout or make it faster;
   • check whether a wrong acs.exit_status field is caught by test/sample-trace.test.ts. If it is not, add a test that catches it.
7. Make the status sentence the same in both writers for every failure kind.

Not in this slice: handshake failures in the converter, and the host-side -32005 entry. Both wait for PR #229 and a Spec ruling, and they are in the fourth slice.

Acceptance: each item above has a test that fails before the change and passes after it.

Do you intend to implement this yourself

Yes. @sabasiddique1 is implementing it. The reviewer is @bar-capsule.

Current Priority Scope

Feeds the runnable Guardian reference implementation