Mirror audit guard seam — WIP work from stale branch parent commit

Background

The parent of the oracle seam work (commit 226356a, "WIP mirror audit guard seam for oracle tests") contains incomplete work on a "mirror audit guard seam" — a test mechanism designed to verify that two code paths (the "oracle" and the live implementation) produce identical or compatible outputs for the same inputs.

The intent appears to be a parity check: given a protocol trace, verify that the current implementation's output matches the recorded oracle output byte-for-byte or within an allowed delta.

Current State

• WIP — not merged, not completed.
• The concept is related to FEAT-008 (oracle guard seams) and is a dependency or companion to that work.

Open Questions

1. What was the "mirror" — two different code paths in the same binary, or a reference implementation in the test harness?
2. What audit property was being verified? (Bit-exact output? Semantic equivalence? Error-handling parity?)

Proposed Action

1. Review the actual diff of commit 226356a against its parent.
2. Determine if the mirror audit approach is compatible with the existing emulebb-build-tests infrastructure.
3. If salvageable: fold into FEAT-008 as the "oracle comparison" phase.
4. If not salvageable: close as Wont-Fix.

Priority

Trivial — depends on FEAT-008 assessment.

Dependency

Blocked on or subsumed by: FEAT-008.