fix(web): 账户弹窗移出 inert；校正快照失败不再静默（BUG-968/969）

账户弹窗与入门付费墙 portal 到 document.body，SidebarInset 的 inert 不再罩住弹窗。
GET 校正快照每个非 200 打 JSON warn；客户端失败显示「这一问还没读到」和重新读取。
下一题是可渲染选择题时，确定性回复正文带题干，挂卡后去重。

frontend/src/components/account-dialog-overlay.tsx

@@ -2,6 +2,7 @@
 
 import { ChevronRight, Settings, UserRound, Users, WalletCards, X } from "lucide-react";
 import { memo, type MutableRefObject, type ReactNode } from "react";
+import { createPortal } from "react-dom";
 
 export type AccountSettingsDialog = "profile" | "chart-library" | "billing" | "general";
 
@@ -60,7 +61,7 @@ export const AccountDialogOverlay = memo(function AccountDialogOverlay({
     return model.renderGeneral();
   };
 
-  return (
+  const overlay = (
     <div className="account-modal-overlay" onMouseDown={model.close}>
       <section
         className={`account-modal ${model.dialogClass}`}
@@ -110,4 +111,9 @@ export const AccountDialogOverlay = memo(function AccountDialogOverlay({
       </section>
     </div>
   );
+  // BUG-968: SidebarInset is inert while the dialog is open. Portal to body so
+  // the dialog is not inside that subtree. SSR keeps the in-tree markup so
+  // renderToString contracts still see the dialog.
+  if (typeof document === "undefined") return overlay;
+  return createPortal(overlay, document.body);
 });

frontend/src/components/onboarding-redeem-paywall.tsx

@@ -3,6 +3,7 @@
 import { Gift, X } from "lucide-react";
 import { useEffect, useRef, useState } from "react";
 import type { FormEvent } from "react";
+import { createPortal } from "react-dom";
 import { keepFocusWithin } from "@/lib/focus-trap";
 import { notifyBalanceChanged, redeemErrorMessage } from "@/lib/membership";
 
@@ -72,7 +73,7 @@ export function OnboardingRedeemPaywall({
     }
   }
 
-  return (
+  const overlay = (
     <div className="account-modal-overlay" onMouseDown={close}>
       <section
         className="account-modal paywall-modal"
@@ -133,4 +134,6 @@ export function OnboardingRedeemPaywall({
       </section>
     </div>
   );
+  if (typeof document === "undefined") return overlay;
+  return createPortal(overlay, document.body);
 }

frontend/src/components/rectification-agentic-chat.tsx

@@ -57,6 +57,8 @@ import {
   RECTIFICATION_QUESTION_RETRY_INTERVAL_MS,
   RECTIFICATION_QUESTION_RETRY_LIMIT,
   RECTIFICATION_QUESTION_UNAVAILABLE_COPY,
+  RECTIFICATION_SNAPSHOT_RETRY_LABEL,
+  RECTIFICATION_SNAPSHOT_UNAVAILABLE_COPY,
   RECTIFICATION_COLLECT_WAITING_PLACEHOLDER,
   RECTIFICATION_DELIVERED_COPY,
   isAbortError,
@@ -74,6 +76,7 @@ import {
   interviewSessionOutcomeFromSnapshot,
   birthTimeSourceFromSnapshot,
   type RectificationCaseSnapshotPayload,
+  type RectificationSnapshotFailure,
 } from "@/lib/rectification-surface-state";
 import { RectificationTimeline } from "@/components/rectification-timeline";
 import {
@@ -430,6 +433,7 @@ export function RectificationAgenticChat(props: RectificationAgenticChatProps) {
   const [questionRetryAttempts, setQuestionRetryAttempts] = useState(0);
   const [questionRepairAttempts, setQuestionRepairAttempts] = useState(0);
   const [questionRepairing, setQuestionRepairing] = useState(false);
+  const [snapshotFailure, setSnapshotFailure] = useState<RectificationSnapshotFailure | null>(null);
   const [openingRequested, setOpeningRequested] = useState(false);
   const [acceptingCandidateId, setAcceptingCandidateId] = useState<string | null>(null);
   const [feedback, setFeedback] = useState<Record<string, "up" | "down" | undefined>>({});
@@ -633,11 +637,16 @@ export function RectificationAgenticChat(props: RectificationAgenticChatProps) {
         `/api/rectification/cases/${encodeURIComponent(caseId)}?sessionId=${encodeURIComponent(sessionId)}`,
         { cache: "no-store", signal: controller.signal },
       );
-      if (!response.ok) return undefined;
+      if (controller.signal.aborted) return undefined;
+      if (!response.ok) {
+        setSnapshotFailure({ status: response.status });
+        return undefined;
+      }
       const payload = await response.json().catch(() => null);
       if (controller.signal.aborted) return undefined;
       const turns = snapshotTurns(payload);
       startTransition(() => {
+        setSnapshotFailure(null);
         applyCaseSnapshot(payload);
         mergeMessages?.(turns);
       });
@@ -645,8 +654,9 @@ export function RectificationAgenticChat(props: RectificationAgenticChatProps) {
         question: currentQuestionFromSnapshot(payload?.current_question),
         turns,
       };
-    } catch {
-      // Snapshot refresh is best-effort; the durable Case remains on the server.
+    } catch (error) {
+      if (isAbortError(error) || controller.signal.aborted) return undefined;
+      setSnapshotFailure({ status: "network" });
       return undefined;
     } finally {
       if (snapshotAbort.current === controller) snapshotAbort.current = null;
@@ -1779,7 +1789,15 @@ export function RectificationAgenticChat(props: RectificationAgenticChatProps) {
               {RECTIFICATION_DELIVERED_COPY}
             </p>
           )}
-          {questionGap === "unavailable" && (
+          {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>
@@ -1828,7 +1846,7 @@ export function RectificationAgenticChat(props: RectificationAgenticChatProps) {
                 ? "点上面的选项即可；想补一句细节再写"
                 : (liveQuestionOnMessages || questionGap === "persisted_question") && collectSpokenPrompt
                   ? "请回答上面的问题…"
-                  : questionGap === "collect_waiting"
+                  : !snapshotFailure && questionGap === "collect_waiting"
                     ? RECTIFICATION_COLLECT_WAITING_PLACEHOLDER
                     : "继续说你记得的人生经历，或回答刚才的问题…"}
             maxLength={RECTIFICATION_COMPOSER_MAX_LENGTH}