test(rectification): lock holdout cards, style-kind scoring, and strong B conflicts

Ask-holdout now requires a renderable choice frame. Scoring uses the same effective contrast kind as rendering, because the engine-varga.d9/d10 fork was live. varga_style weak_yes counts as a strong conflict; existence weak_yes still does not.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/lib/rectification-agentic/core/candidate-contrast-packet.ts

@@ -591,6 +591,7 @@ export function conflictProbesFromContrast(
       ...row.conflictsCandidateIds,
     ]))];
     if (candidateIds.length < 2) return [];
+    const choiceKind = effectiveContrastChoiceKind(probe);
     return [{
       id: probe.probeId,
       semantic_key: probe.semanticKey,
@@ -602,10 +603,10 @@ export function conflictProbesFromContrast(
       expected_outcomes: outcomes,
       information_gain: probe.informationGain,
       source: "varga_contrast",
-      ...(probe.choiceKind === "varga_style"
-        || probe.choiceKind === "event_quality"
-        || probe.choiceKind === "existence"
-        ? { choice_kind: probe.choiceKind }
+      ...(choiceKind === "varga_style"
+        || choiceKind === "event_quality"
+        || choiceKind === "existence"
+        ? { choice_kind: choiceKind }
         : {}),
     }];
   });