docs(spec): ApprovalDecisionResult records what the stranded-decision throw carries

The contract already declared the posture: a decision that finalises a
flow-bound request and cannot resume its own run throws rather than
answering `resumed: false`, because a recorded decision whose flow never
advances is #4420's zombie half-state. What it never said is that the
throw is now readable.

The maintainer ruling #13807 (2026-09-04, decision batch #37) owes both
halves — "throws with the decision and run identified; the fields are the
published way to read it" — and only the first half was written down. The
`resumed` docblock now names the second: the 500-class `RESUME_FAILED`
carries `finalized`, `decision`, `runId` and `repairable` on its ERROR
body as `StrandedDecisionDetails` (`@objectstack/types`, attached by
`strandedDecisionFailure`, read back by `strandedDecisionDetails`, merged
into the response by the REST approvals door), and the status code does
not move because a durable decision over a run that will not advance is
still a failure.

Prose only. No member is added: the four facts ride the ERROR, so putting
them on this success shape would declare a shape that never carries them,
and the docblock says so explicitly. It also keeps them distinct from
`resumeFailure`, which reports the #16472 family's different event — a
resume failure told behind an answer that still succeeded.

The changeset is owed on the second half of the two-part test, not the
first: `src/contracts/approval-service.ts` is outside `packages/spec`'s
`files[]`, but the changed docblock text is emitted into
`dist/contracts/index.d.ts` and `index.d.mts`, which `files[]` publishes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016N6xmWt5hYm94ffVEwGH8x

Author: claude

.changeset/approval-decision-result-stranded-throw-is-readable.md

@@ -0,0 +1,11 @@
+---
+"@objectstack/spec": patch
+---
+
+`ApprovalDecisionResult`'s contract docblock now records what the stranded-decision throw carries — execution item 2 of the #13807 ruling (maintainer 2026-09-04, decision batch #37).
+
+The posture itself was already declared: a decision that finalises a flow-bound request and cannot resume its own run throws rather than answering `resumed: false`, because a recorded decision whose flow never advances is #4420's zombie half-state. What the docblock did not say is that the throw is now *readable*. The ruling's item 2 owes both halves — "throws with the decision and run identified; the fields are the published way to read it" — and only the first half was written down.
+
+- **Prose only. No member moves.** `finalized`, `decision`, `runId` and `repairable` ride the ERROR body of the 500-class `RESUME_FAILED`, as `StrandedDecisionDetails` (`@objectstack/types`, attached by `strandedDecisionFailure`, read back by `strandedDecisionDetails`, merged into the response by the REST approvals door). Adding them to `ApprovalDecisionResult` would declare a success shape that never carries them, so the docblock names them where they actually live and says so explicitly.
+- **The status code does not move either.** A durable decision over a run that will not advance is still a failure; what the ruling changed is that a caller holding the status code alone no longer has to read a bare 500 as "the decision did not happen" when the row is terminal.
+- **Kept distinct from `resumeFailure`.** That member is the #16472 family's different event — a resume failure told *behind an answer that still succeeded* — and the new paragraph says so, so the two carriers are not read as one.

packages/spec/src/contracts/approval-service.ts

@@ -735,6 +735,26 @@ export interface ApprovalDecisionResult {
    * whose parent then stranded (#15556) still answers `true`, and the
    * parent's strand is told on {@link resumeFailure} — carried on the
    * success answer per the #16472 ruling, never thrown.
+   *
+   * What that throw carries is published, not prose only (#13807, maintainer
+   * ruling 2026-09-04, decision batch #37). The status code does not move — a
+   * durable decision over a run that will not advance is still a failure —
+   * but the 500-class `RESUME_FAILED` it raises names, on its ERROR body, the
+   * four facts a caller needs: `finalized` (the decision stands), `decision`,
+   * `runId`, and `repairable` — the engine's own `'stranded'` discriminator
+   * carried through, never inferred from the message text. That envelope is
+   * `StrandedDecisionDetails` (`@objectstack/types`), attached by
+   * `strandedDecisionFailure` and read back by `strandedDecisionDetails`; the
+   * REST approvals door merges it into the `RESUME_FAILED` response body.
+   * Those four facts are the published way to read the posture this member
+   * declares — a caller holding only the status code reads a bare 500 as "the
+   * decision did not happen", and the row IS terminal.
+   *
+   * ⛔ They are not members of this result and must never be added to it:
+   * they ride the ERROR, so declaring them here would declare a success shape
+   * that never carries them. ⛔ Nor are they {@link resumeFailure}, which
+   * reports the other event of the #16472 ruling — a resume failure behind an
+   * answer that still succeeded.
    */
   resumed?: boolean;
   /**