fix(sessions): keep rectification result titles when a new chat opens

The case insert trigger writes the result time, then the existing open persist sends the minted title back. A before-update guard keeps that result unless the user chose a non-automatic name, and a new session reads the stored title into the sidebar.

frontend/src/hooks/use-rectification-surface.ts

@@ -3,6 +3,7 @@
 import { useEffect, useRef, useState, type Dispatch, type MutableRefObject, type SetStateAction } from "react";
 
 import { resolveSessionTitle } from "@/lib/agent-reply";
+import { fetchSessionDetail } from "@/lib/home-cloud-sync";
 import { rectificationOpenIdentity } from "@/lib/rectification-session-open";
 import { showChatNotice as setComposerNotice } from "@/lib/chat-notice";
 import { writeSessionUrl } from "@/lib/chat-session-url";
@@ -292,6 +293,17 @@ export function useRectificationSurface(params: RectificationSurfaceParams) {
       };
       setSessions((current) => [merged, ...current.filter((session) => session.id !== merged.id)]);
       void persistSession(merged).catch(() => {});
+      // New sessions have no local title to preserve (BUG-699). The case insert
+      // trigger already wrote the result title. Read that back so the sidebar
+      // does not keep the minted "生时校正" after persist.
+      if (!existing) {
+        void fetchSessionDetail(opened.sessionId, modelCatalog).then((serverSession) => {
+          if (!serverSession || serverSession.sessionType !== "birth_time_rectification") return;
+          updateSession(opened.sessionId, (session) => (
+            session.title === serverSession.title ? session : { ...session, title: serverSession.title }
+          ));
+        }).catch(() => {});
+      }
 
       // One reveal: turns and snapshot are read before the surface mounts, so
       // the reader never sees an empty transcript or an empty question area