refactor(rectification): split the chat component into hooks, parameter functions and blocks

Move-only (TASK-rectification-code-split-20260926 T1/T4). No behavior, API,
copy, DB, Skill or scoring change.

- rectification-agentic-chat.tsx: 2043 -> 737 lines; component body
  1625 -> 630; useState 35 -> 12, useRef 16 -> 9, effects 9 -> 5,
  useCallback 12 -> 6.
- Snapshot sync -> hooks/use-rectification-case-snapshot.ts; board layout
  and live label clock -> two small hooks.
- send / submitStructuredChoice / acceptCandidate bodies ->
  lib/rectification-chat-{turn,choice,accept}-run.ts parameter functions
  (bodies verbatim, deps destructured to the same names); copy/regenerate,
  question repair, pure transcript and snapshot helpers and the per-render
  view derivation -> lib/rectification-chat-*.ts (no React hooks).
- Question-gap blocks and the read-only range line ->
  components/rectification-question-gap-notices.tsx.
- Dependency arrays kept exactly as before (lint warnings +3, listed in
  PROGRESS); no dep added to appease the linter.
- Tests: whole-source contracts read tests/rectification-chat-surface.ts
  (container + split files, like home-surface.ts); slices of moved code now
  call the extracted functions or render the extracted block, each with a
  原值/新值/原因 comment. New tests/rectification-growth-contract.test.ts.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017eEAG8HD3mm8gsKXgk8uU8

frontend/src/components/rectification-question-gap-notices.tsx

@@ -0,0 +1,151 @@
+"use client";
+
+import {
+  RECTIFICATION_DELIVERED_COPY,
+  RECTIFICATION_QUESTION_PREPARING_LABEL,
+  RECTIFICATION_QUESTION_RELOAD_LABEL,
+  RECTIFICATION_QUESTION_REPAIR_FAILED_COPY,
+  RECTIFICATION_QUESTION_REPAIR_LIMIT,
+  RECTIFICATION_QUESTION_UNAVAILABLE_COPY,
+  RECTIFICATION_SNAPSHOT_RETRY_LABEL,
+  RECTIFICATION_SNAPSHOT_UNAVAILABLE_COPY,
+  persistedQuestionSurface,
+  rectificationReadonlyRangeCopy,
+  type RectificationSnapshotFailure,
+} from "@/lib/rectification-surface-state";
+import type { ChoiceKey, RectificationChoiceCard as ChoiceCardModel } from "@/lib/rectification-agentic/v9/choice-card";
+import type { CurrentQuestionModel } from "@/lib/rectification-chat-snapshot";
+import type { RectificationChatView } from "@/lib/rectification-chat-view";
+import { Button } from "@/components/ui/button";
+import { ConsultationTimelineLiveRow } from "./consultation-run-timeline";
+import { RectificationChoiceCard } from "./rectification-choice-card";
+
+export function RectificationReadonlyRange({
+  range,
+  sessionOutcome,
+  discriminatingEventProbes,
+  contrastProbes,
+}: Readonly<{
+  range: readonly [string, string];
+  sessionOutcome: string | null;
+  discriminatingEventProbes: unknown;
+  contrastProbes: unknown;
+}>) {
+  return (
+    <p className="rectification-readonly-range" role="status">
+      {rectificationReadonlyRangeCopy({
+        range,
+        sessionOutcome,
+        discriminatingEventProbes,
+        contrastProbes,
+      })}
+    </p>
+  );
+}
+
+/**
+ * The blocks under the transcript that stand in for a missing next question:
+ * the standalone persisted question (only when no assistant message can carry
+ * it), the preparing row, the delivered note, the snapshot-failure retry, the
+ * repair button, and the verified-idle note. Moved out of
+ * RectificationAgenticChat unchanged (TASK-rectification-code-split-20260926).
+ */
+export function RectificationQuestionGapNotices({
+  view,
+  currentQuestion,
+  choiceCard,
+  choiceNonce,
+  busy,
+  readonly,
+  snapshotFailure,
+  questionRepairAttempts,
+  questionRepairing,
+  submitChoice,
+  submitStop,
+  refetchQuestion,
+  repairQuestion,
+}: Readonly<{
+  view: Pick<RectificationChatView, "showStandaloneQuestion" | "questionGap" | "showSelectionCards" | "verifiedIdleCopy">;
+  currentQuestion: CurrentQuestionModel | null;
+  choiceCard: ChoiceCardModel | null;
+  choiceNonce: number;
+  busy: boolean;
+  readonly: boolean;
+  snapshotFailure: RectificationSnapshotFailure | null;
+  questionRepairAttempts: number;
+  questionRepairing: boolean;
+  submitChoice: (key: ChoiceKey) => void;
+  submitStop: () => void;
+  refetchQuestion: () => Promise<void>;
+  repairQuestion: () => Promise<void>;
+}>) {
+  const { showStandaloneQuestion, questionGap, showSelectionCards, verifiedIdleCopy } = view;
+  return (
+    <>
+      {showStandaloneQuestion && currentQuestion?.prompt && (
+        <div className="rectification-message-wrap rectification-message-entry" data-testid="persisted-question">
+          <div className="rectification-message-question is-standalone">
+            {persistedQuestionSurface({
+              questionKind: currentQuestion.kind,
+              hasChoiceCard: Boolean(choiceCard),
+              questionPersisted: true,
+            }) === "choice_card" && choiceCard ? (
+              <>
+                <p className="rectification-message-question__prompt">{currentQuestion.prompt}</p>
+                <RectificationChoiceCard
+                  key={`${choiceCard.question_id}:${choiceNonce}:persisted`}
+                  variant="embedded"
+                  card={choiceCard}
+                  pending={busy}
+                  disabled={busy || readonly}
+                  selectedKey=""
+                  onSelect={submitChoice}
+                  onStop={submitStop}
+                />
+              </>
+            ) : (
+              <p className="rectification-message-question__prompt">{currentQuestion.prompt}</p>
+            )}
+          </div>
+        </div>
+      )}
+      {questionGap === "preparing" && (
+        <div className="rectification-message-wrap rectification-message-entry rectification-question-gap">
+          <ConsultationTimelineLiveRow id="question-preparing" label={RECTIFICATION_QUESTION_PREPARING_LABEL} />
+        </div>
+      )}
+      {questionGap === "delivered" && !showSelectionCards && (
+        <p className="rectification-pending-note" role="status">
+          {RECTIFICATION_DELIVERED_COPY}
+        </p>
+      )}
+      {snapshotFailure && (
+        <div className="rectification-message-wrap rectification-message-entry rectification-question-gap" role="status">
+          <p className="rectification-question-gap__copy">{RECTIFICATION_SNAPSHOT_UNAVAILABLE_COPY}</p>
+          <Button type="button" variant="outline" onClick={() => void refetchQuestion()}>
+            {RECTIFICATION_SNAPSHOT_RETRY_LABEL}
+          </Button>
+        </div>
+      )}
+      {questionGap === "unavailable" && !snapshotFailure && (
+        <div className="rectification-message-wrap rectification-message-entry rectification-question-gap" role="status">
+          {questionRepairAttempts >= RECTIFICATION_QUESTION_REPAIR_LIMIT ? (
+            <p className="rectification-question-gap__copy">{RECTIFICATION_QUESTION_REPAIR_FAILED_COPY}</p>
+          ) : (
+            <>
+              <p className="rectification-question-gap__copy">{RECTIFICATION_QUESTION_UNAVAILABLE_COPY}</p>
+              <Button type="button" variant="outline" onClick={() => void repairQuestion()} disabled={questionRepairing}>
+                {RECTIFICATION_QUESTION_RELOAD_LABEL}
+              </Button>
+            </>
+          )}
+        </div>
+      )}
+      {questionGap === "verified_idle" && verifiedIdleCopy && !showSelectionCards && (
+        <p className="rectification-pending-note" role="status">
+          {verifiedIdleCopy}
+        </p>
+      )}
+    </>
+  );
+}