fix(rectification): surface dropped probes and filter tools by the decision

Silent unrenderable discriminators, a missing question-contract golden, and a always-on tool table were hiding fail-closed drops behind the prompt wall.

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

frontend/tests/rectification-answer-choice.test.ts

@@ -760,6 +760,47 @@ test("turn_decision stays inside the configured byte budget", () => {
   assert.ok(!("baseline_birth_snapshot" in projection));
 });
 
+test("unrenderable focus schema stays visible as current_question, not null", () => {
+  const snapshot = candidateSnapshotFixture();
+  Object.assign(snapshot.decision_receipt, { inference_state: inferenceState() });
+  const dossier = parseV9CaseDossier(dossierFixture({
+    latestResult: snapshot,
+    conversationSummary: conversationSummaryFixture({
+      activeFocus: activeFocusFixture({
+        expectedAnswerSchema: { choice: { prompt: "坏题" } },
+      }),
+    }),
+  }));
+  assert.ok(dossier);
+  const projection = projectTurnDecision(dossier);
+  const currentQuestion = projection.current_question as {
+    unrenderable?: boolean;
+    reason?: string;
+    prompt?: string | null;
+  } | null;
+  assert.equal(currentQuestion?.unrenderable, true);
+  assert.equal(currentQuestion?.reason, "invalid_choice_schema");
+  assert.equal(currentQuestion?.prompt, null);
+  assert.equal(projection.current_probe, null);
+});
+
+test("collection focus without choice copy is not an unrenderable current_question", () => {
+  const snapshot = candidateSnapshotFixture();
+  Object.assign(snapshot.decision_receipt, { inference_state: inferenceState() });
+  const dossier = parseV9CaseDossier(dossierFixture({
+    latestResult: snapshot,
+    conversationSummary: conversationSummaryFixture({
+      activeFocus: activeFocusFixture({
+        intent: "clarify_event_date",
+        expectedAnswerSchema: { required: ["month"] },
+      }),
+    }),
+  }));
+  assert.ok(dossier);
+  const projection = projectTurnDecision(dossier);
+  assert.equal(projection.current_question, null);
+});
+
 test("turn_decision hides current_probe unless a valid current_question exists", () => {
   const withFocus = projectTurnDecision(parseV9CaseDossier(choiceDossier())!);
   assert.ok(withFocus.current_question);