Add acceptance runner adapter and persist mutation state

Add the persistent runner adapter for gherkin-mutator and commit the
differential/acceptance mutation manifests written by the approved tools
during the architect verification pass for the post-memo feature.

By architect.

docs/reviews/post-memo-summary.md

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+# Architectural Review Summary — post-memo
+
+## Task and commits reviewed
+- Task: `post-memo`
+- Reviewed the merged branch ending at `8e2693ad08` (refactorer), which carried:
+  - `d071b21`/`c9556be` — specifier Post-a-Memo Gherkin spec + feature backlog
+  - `514298b` — coder implementation with acceptance pipeline
+  - `64a7f78` — refactorer merge of coder work
+  - `8e2693a` — refactorer memo-post complexity reduction
+- Merged into `swarmforge-architect` (fast-forward) and processed as a batch.
+
+## Architectural findings and fixes applied
+Reviewed UI/Core separation, dependency rule, information hiding/encapsulation, and
+local code quality.
+
+1. **Testable core behind small adapters (good).** `src/services/memo-post.js` is a
+   testable module free of UI/IO concerns. It injects `wallet` and `feed` adapters
+   (minimal-slp-wallet surface + feed reflection), so OP_RETURN/broadcast and UI
+   concerns stay outside the core. Environmentally unsuitable I/O is confined to
+   adapter boundaries. Dependency direction is inward.
+2. **Acceptance pipeline separation (good).** `acceptance/lib/{generate,runtime,handlers}`
+   are the project-specific components the APS spec prescribes. The feature is parsed
+   by the **APS-supplied Babashka `gherkin-parser`** (procured fresh from
+   github.com/unclebob/Acceptance-Pipeline-Specification on first use), not
+   reimplemented. `handlers.js` drives real core behavior through fake wallet/feed
+   adapters so the run is deterministic and offline.
+3. **Information hiding (good).** memo-post hides the Memo `0x6d02` prefix and
+   broadcast mechanics; handlers only assert observable outcomes (broadcast prefix,
+   feed reflection, empty/length rejection).
+4. **Fix applied — runner adapter added.** Built the project-specific persistent
+   runner adapter required by `gherkin-mutator` at
+   `acceptance/lib/runner-worker.js` (newline-delimited JSON protocol; evaluates each
+   mutated feature IR through the same runtime/handlers and reports
+   `test_failure|test_success|infrastructure_error`).
+5. **Manifests updated by tools (permitted).** The language mutation tool embedded
+   its differential footer manifest in `src/services/memo-post.js`; the APS mutator
+   wrote the acceptance-mutation scenario manifest into `specs/post-memo.feature`.
+   Both are normal tool output and were left for the tooling, not hand-edited.
+
+## Verification results
+- **Unit (`node --test`):** 7/7 pass (`memo-post.test.js`).
+- **Acceptance (normal):** all 6 scenario executions pass.
+- **Mutation (`mutate4javascript` differential, `--max-workers 8`):**
+  `memo-post.js` — **killed 7, survived 0, uncovered 0**. Full kill.
+- **DRY (`dry4javascript src`):** no duplicate candidates.
+- **Gherkin acceptance mutation (soft):** 6 discovered; **1 killed**, **5 survived**,
+  0 errors.
+  - Killed: the empty-memo boundary — dithering the `"  "` example makes the
+    validation branch fail the scenario, confirming the empty-rejection guardrail is
+    connected to the example data.
+  - Survived (documented equivalents): message-content dithers in the valid-memo
+    scenario and the over-long scenarios. The tests treat the message as opaque data
+    and assert the *same* (mutated) text is composed and reflected, so changing one
+    character leaves the exercised branch identical. These are acceptable equivalent
+    survivors, not missing guardrails.
+- **Property tests:** none present in this project.
+
+## Suite status
+- Unit + acceptance suites pass; mutation fully kills source-level mutants for the
+  testable core. Gherkin acceptance mutation has 5 documented-equivalent survivors.
+
+## Handoffs sent
+- `git_handoff` → coder, refactorer (priority `00`, task `post-memo`), to review the
+  architectural commit (runner adapter + tool manifests).
+
+By architect.