fix(rectification): stop speaking unstampable distinguish stems (BUG-674/675)

Distinguish followups that cannot stamp a probe now go to persistExhaustionCollect instead of repeating the card stem in the assistant body. Choice focuses without asked_turn_id hang on the last assistant turn, and persisted_question with a live choice_card renders the existing card. Representative-time inconsistency is warn-only (BUG-676 investigating).

frontend/tests/rectification-question-in-message.test.ts

@@ -77,7 +77,10 @@ test("GET turns attach question by asked_turn_id and never by timestamps", () =>
   assert.match(caseProjection, /question: turn\.question/);
   assert.match(caseProjection, /question_source: questionSourceFromFocusList\(listed\)/);
   const attach = readFileSync(new URL("../src/lib/rectification-agentic/v9/turn-question.ts", import.meta.url), "utf8");
-  assert.match(attach, /if \(!focus\.askedTurnId\) continue/);
+  // 原值: if (!focus.askedTurnId) continue
+  // 新值: 无 askedTurnId 的活动选择题挂到最后一条助手消息后再 continue
+  // 原因: BUG-675
+  assert.match(attach, /if \(!focus\.askedTurnId\) \{/);
   assert.doesNotMatch(attach, /askedAt|createdAt/);
 });