fix(voyage): inject plan_critic via Phase 9 readAndUpdate (906f155d)

plugins/voyage/commands/trekplan.md

@@ -726,6 +726,47 @@ After both complete:
 - If only **minor** issues or clean: proceed without changes. Note the
   review result in the plan.
 
+### Inject plan_critic verdict into plan frontmatter (post-dedup, post-revise)
+
+After the dedup pass completes and any blocker/major revisions are folded
+in, atomically update the plan's frontmatter with the plan-critic verdict
+so downstream surfaces (notably `playground/voyage-playground.html`
+`buildArtifactKeyStat`) can read it without re-parsing the review JSON.
+
+Phase 8 (write plan) precedes Phase 9 (adversarial review), so the
+verdict cannot be in Phase 8's frontmatter template — it must be
+injected here, after the verdict exists.
+
+Read the verdict from `/tmp/plan-critic-out.json` and apply it via
+`lib/util/markdown-write.mjs` `readAndUpdate`:
+
+```js
+import { readFileSync } from 'node:fs';
+import { readAndUpdate } from `${CLAUDE_PLUGIN_ROOT}/lib/util/markdown-write.mjs`;
+
+const criticVerdict = JSON.parse(readFileSync('/tmp/plan-critic-out.json', 'utf-8')).verdict;
+const result = readAndUpdate(planPath, ({ frontmatter, body }) => {
+  frontmatter.plan_critic = criticVerdict;
+  return { frontmatter, body };
+});
+if (!result.valid) {
+  // Non-fatal: log warning. plan.md already exists from Phase 8;
+  // missing plan_critic is degraded UX, not blocking.
+  console.warn('plan_critic injection failed:', result.errors);
+}
+```
+
+Field semantics:
+- `plan_critic` — string. One of `APPROVE`, `APPROVE_WITH_NOTES`,
+  `REVISE`, or `BLOCK`. Matches the rubric in `plan-critic` agent
+  output. Omitted when the inject failed (Phase 9 surfaces a warning
+  in that case but does not abort).
+
+Schema compatibility: `plan_critic` is **additive and optional**. The
+plan validator (`lib/validators/plan-validator.mjs`) tolerates unknown
+frontmatter keys, so this addition does NOT require a `plan_version`
+bump. Plans written before this field was added validate identically.
+
 ## Phase 10 — Present and refine
 
 Present a summary to the user:

plugins/voyage/tests/lib/doc-consistency.test.mjs

@@ -625,3 +625,24 @@ test('docs/annotation-quickstart.md exists with ≤7 numbered steps and example-
     `${path} must reference the canonical example fixture for hands-on verification`,
   );
 });
+
+test('commands/trekplan.md Phase 9 documents plan_critic injection via readAndUpdate (906f155d)', () => {
+  // Phase 9 (adversarial review) writes the plan-critic verdict back into
+  // plan.md frontmatter AFTER plan-review-dedup completes. The inject must
+  // happen post-Phase-8 (write) because Phase 8 precedes Phase 9 in the
+  // pipeline — the value cannot be in Phase 8's frontmatter template.
+  // Both the field name (plan_critic) and the inject mechanism
+  // (readAndUpdate from lib/util/markdown-write.mjs) must be documented
+  // so future maintainers can trace the contract.
+  const text = read('commands/trekplan.md');
+  assert.match(
+    text,
+    /plan_critic/,
+    'commands/trekplan.md must document plan_critic frontmatter field (906f155d)',
+  );
+  assert.match(
+    text,
+    /readAndUpdate/,
+    'commands/trekplan.md must reference readAndUpdate from lib/util/markdown-write.mjs (906f155d)',
+  );
+});