## Summary
Reviewed immutable revision `stage-38-revision.md` at SHA-256 `0047d53be842ef9bbc5990c826e617777f535fc6af73722ecc0f7dada84ec0a5`. It closes the sole Stage-37 terminal-outcome defect: receipt-backed but not yet audited delivery is now a distinct no-send/reconciliation outcome rather than being collapsed into a duplicate. The closed union, deterministic precedence, fail-closed conflict rule, and replay/restart matrix preserve the no-resend boundary.

## Claims
- The RALPLAN index records revision stage 38 with the reviewed path and assigned SHA-256 (`index.jsonl:50`).
- Stage 37 assigned every exact receipt/delivered/audit-pending/sent-audited/unknown terminal chain to `DiagnosticDuplicateNoSend`, while separately allowing reconciliation; that conflated a replay-safe final completion with a receipt-known audit-recovery state (`stage-37-revision.md`, “Existing dedupe-state matrix”).
- Revision 38 defines a sealed result algebra with one authority-bearing `VerifiedDiagnosticReservation` and three explicit no-send variants: unknown, audit-pending, and duplicate. Every no-send variant has `provider_authority=false` (`stage-38-revision.md:163-169`).
- The new chain precedence selects duplicate only for valid `sent_audited`, selects audit-pending for a valid receipt/delivered/audit-pending chain, selects unknown for existing or newly terminalized receipt-less starts/consumes, and rejects malformed/conflicting chains without a row or provider delta (`stage-38-revision.md:171-178`).
- `DiagnosticHost.deliver` returns no-send variants before provider-start branching, and reconciliation may only advance a valid audit-pending chain to `sent_audited`; it never restores send permission to unknown (`stage-38-revision.md:180-182`).

## Analysis
### Spec compliance
The Stage-37 behavior could truthfully prevent a resend but could not truthfully tell the operator whether a provider receipt existed and a reconciliation action was still required: both audit-pending and completed chains surfaced as duplicate. That conflicts with the approved P4 contract, which requires provider-success/audit-failure to say that the receipt is known, forbid resend, and permit audit recovery, while completion is only reported after `sent_audited` (`stage-23-final.md`, “P2–P6 Exact UI, Rows, and Cleanup”).

Revision 38 supplies exactly the missing terminal distinction. Its Korean `DiagnosticAuditPendingNoSend` text is unambiguously no-retry and directs only audit recovery; `DiagnosticDuplicateNoSend` is reserved for a valid `sent_audited` completion. The explicit receipt/delivered/audit-pending priority also means that a replay cannot fall into the fresh-authority path. This meets the Stage-37 finding without extending product scope.

### Architecture and safety
The union is closed at the authority boundary, not only in presentation code. `reserve_and_verify`/host dispatch can make provider admission exhaustively conditional on `VerifiedDiagnosticReservation`; all existing evidence is terminal no-send. Startup recovery uses the same validated chain semantics, so a restart cannot reinterpret a persisted start, receipt, or audit-pending chain as new send authority.

The conflict rule is appropriately conservative. A receipt mixed with unknown absent the defined audit-pending normalization, multiple conflicting receipts/terminals, or illegal order yields `DiagnosticReservationConflict` with provider zero instead of best-effort status selection. That preserves the durable-at-most-once invariant and avoids a compatibility fallback that could conceal contradictory evidence.

### Antithesis and synthesis
Collapsing all existing terminal evidence to `duplicate` is simpler and still blocks delivery. It is unsafe operationally because an operator cannot distinguish an already-audited completion from a durable provider receipt requiring audit repair; callers could either abandon necessary reconciliation or invent a side path. The selected three no-send variants retain the simple no-send provider boundary while exposing only the one allowed next mutation for receipt-backed audit recovery.

## Root Cause
Stage 37 overloaded `DiagnosticDuplicateNoSend` for two materially different durable states: final `sent_audited` completion and provider-receipt/audit-pending recovery. The overload erased the authoritative operator outcome despite correctly denying provider authority.

## Findings
No remaining findings. The sole Stage-37 terminal-outcome finding is closed by the typed audit-pending outcome, ordered validated-chain projection, provider-zero host handling, and enumerated replay/restart tests.

## Recommendations
1. Implement the result as an exhaustive sealed union and permit `verify_provider_start`/transport only for `VerifiedDiagnosticReservation`.
2. Keep the stated validator precedence and fail-closed conflict behavior; do not reintroduce a generic terminal-to-duplicate fallback.
3. Require the listed matrix tests to assert exact class, status, Korean text, reconciliation availability, row delta, and provider delta in both process-local replay and restart recovery.

## Architectural Status
CLEAR

## Code Review Recommendation
APPROVE

## Tradeoffs
- **Selected typed no-send outcomes:** preserves provider-zero safety while exposing the only valid audit-recovery action; adds a small exhaustive result mapping.
- **Single duplicate outcome:** smaller surface but loses the receipt-known/audit-pending distinction required by P4; reject.
- **Treat audit-pending as sendable after restart:** could repair uncertainty automatically but violates the terminal no-resend contract; reject.