fix(evals): AUQ A/B vendored pre-cut arm + judge-error inconclusive taxonomy

- The PRE arm read a branch-local SHA (3263fffe) that becomes unreachable on
  fresh clones after the squash-merge; the pre-cut render is now a vendored
  fixture.
- A judge failure on one side no longer coerces substance to 0 (which
  fabricated DEGRADATION on POST-side failures and masked regressions on
  PRE-side failures): null substance = inconclusive, format still gates.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/skill-e2e-auq-repetition-cut-ab.test.ts

@@ -15,41 +15,48 @@
  * NOT WORSE than the pre-cut AUQ on format elements and recommendation
  * substance. Same harness and bar as skill-e2e-auq-verbose-vs-carved-ab.
  *
- *   - PRE  : plan-ceo-review/SKILL.md read from git at 3263fffe (the last
+ *   - PRE  : the pre-cut plan-ceo-review/SKILL.md render, vendored at
- *            commit before the cut), with the current sections/ (the cut
+ *            test/fixtures/auq-pre-cut-plan-ceo-review-SKILL.md (captured
- *            touched only the preamble skeleton, not the sections).
+ *            from branch commit 3263fffe, the last commit before the cut —
+ *            vendored because that SHA is branch-local and unreachable from
+ *            fresh clones after the squash-merge), with the current
+ *            sections/ (the cut touched only the preamble skeleton).
  *   - POST : this worktree's render.
  */
 import { test } from 'bun:test';
 import { describeE2ETier } from './helpers/e2e-gate';
 import * as fs from 'node:fs';
+import * as path from 'node:path';
 import {
   setupPlanCeoDir,
   captureModeSelectionAuq,
   scoreAuqFormat,
   carvedSkill,
-  verboseSkill,
 } from './helpers/auq-sdk-capture';
 import { judgeRecommendation } from './helpers/llm-judge';
 
 const describeE2E = describeE2ETier('periodic');
 const runId = `auq-cut-ab-${process.env.EVALS_RUN_ID ?? 'local'}`;
-const PRE_CUT_REF = '3263fffe';
+const PRE_CUT_FIXTURE = path.join(import.meta.dir, 'fixtures', 'auq-pre-cut-plan-ceo-review-SKILL.md');
 
 async function grade(label: string, dir: string) {
   const text = await captureModeSelectionAuq({ planDir: dir, testName: `auq-cut-ab-${label}`, runId });
   const fmt = scoreAuqFormat(text);
-  let substance = 0;
+  // null = judge unavailable. Never coerced to 0: a transient judge failure
+  // on one side must read as INCONCLUSIVE, not as a fabricated degradation
+  // (POST-side failure) or a masked regression (PRE-side failure) — same
+  // taxonomy as armJudge's judge_error cells.
+  let substance: number | null = null;
   if (text.trim()) {
     try {
       const r = await judgeRecommendation(text);
       substance = r.reason_substance;
-    } catch { /* judge unavailable */ }
+    } catch { /* judge unavailable — recorded as null */ }
   }
   // eslint-disable-next-line no-console
   console.log(
     `[AUQ-CUT-AB ${label}] captured=${text.length}B format=${fmt.present}/${fmt.total} ` +
-      `missing=[${fmt.missing.join(',')}] substance=${substance}`,
+      `missing=[${fmt.missing.join(',')}] substance=${substance ?? 'inconclusive'}`,
   );
   return { text, fmt, substance };
 }
@@ -65,7 +72,7 @@ describeE2E('AUQ no-degradation: repetition cut (periodic)', () => {
         tmpPrefix: 'auq-cut-ab-post-',
       });
       const preDir = setupPlanCeoDir({
-        skillMd: verboseSkill(PRE_CUT_REF),
+        skillMd: fs.readFileSync(PRE_CUT_FIXTURE, 'utf-8'),
         sectionsFrom: post.sectionsFrom,
         tmpPrefix: 'auq-cut-ab-pre-',
       });
@@ -80,8 +87,8 @@ describeE2E('AUQ no-degradation: repetition cut (periodic)', () => {
       }
 
       const summary = [
-        `POST: format ${q.fmt.present}/${q.fmt.total}, substance ${q.substance}`,
+        `POST: format ${q.fmt.present}/${q.fmt.total}, substance ${q.substance ?? 'inconclusive'}`,
-        `PRE : format ${p.fmt.present}/${p.fmt.total}, substance ${p.substance}`,
+        `PRE : format ${p.fmt.present}/${p.fmt.total}, substance ${p.substance ?? 'inconclusive'}`,
       ].join('\n');
 
       if (!q.text.trim() || !p.text.trim()) {
@@ -92,7 +99,14 @@ describeE2E('AUQ no-degradation: repetition cut (periodic)', () => {
       }
 
       const formatRegressed = q.fmt.present < p.fmt.present;
-      const substanceRegressed = q.substance < p.substance - 1; // 1-pt judge tolerance
+      // Substance compares only when BOTH judge calls succeeded; a null on
+      // either side logs as inconclusive and the format comparison still gates.
+      const substanceComparable = q.substance !== null && p.substance !== null;
+      if (!substanceComparable) {
+        // eslint-disable-next-line no-console
+        console.log('[AUQ-CUT-AB] substance inconclusive (judge error on at least one side) — format elements still compared.');
+      }
+      const substanceRegressed = substanceComparable && q.substance! < p.substance! - 1; // 1-pt judge tolerance
       if (formatRegressed || substanceRegressed) {
         throw new Error(
           `AUQ DEGRADATION from the repetition cut — the gate outranks the approval; revert the cut:\n${summary}` +