[S-04] Override status masks real authorization verdict — compliance reporting risk

## Summary

**Severity:** P2 — Compliance Reporting Risk
**Phase:** Phase 4 Remediation (API Contract Hardening)
**Audit Reference:** SPIN Agent Product Integrity Report, Phase 1

## Finding

The override status mechanism (S-04) replaces the displayed authorization status with the override value, masking the underlying compliance verdict. A system that is not authorized can appear authorized. The original verdict is not preserved or visible alongside the override indicator.

## Impact

- Compliance reports may inaccurately show systems as authorized
- Auditors and AOs cannot see the underlying verdict when an override is in effect
- Potential FedRAMP/DoD compliance finding if used in a live environment
- Violates audit trail requirements (no record of what was overridden)

## Required Behavior

Overrides should be displayed as an **annotation on top of** the underlying verdict, not as a replacement. Both values must be visible and the override must include: who applied it, when, and the justification.

## Acceptance Criteria

- [ ] Underlying authorization verdict is preserved in the database regardless of override
- [ ] UI displays both: underlying verdict AND override annotation
- [ ] Override record captures: actor, timestamp, justification, expiry
- [ ] E2E test: apply override → assert underlying verdict still queryable
- [ ] Compliance export uses underlying verdict (or flags override explicitly)

## Related

- #830 — AO Decision record (prerequisite for clean authorization state)
- #675 — Authorization export without AO Risk Acceptance Statement
- Audit artifact: SPIN Agent Product Integrity Report (Phase 1)

Start by tracing the S-04 override status mechanism across the authorization database, UI, and compliance export, using #830 as prerequisite context. Verify the existing end-to-end path for applying an override, then use the listed acceptance criteria to define completion: preserved and queryable verdicts, visible override metadata, expiry, and explicit export handling.

Written by the indexing model from the issue text.