fix(chat): keep rectification sessions findable and keep the delivery card

Rectification answers now advance chat_sessions.updated_at (BUG-704).
A ?c= id missing from the loaded page is fetched before anyone may call
it deleted (BUG-705). The range card no longer has a post-card tie-break
button; live questions leave the card visible with adopt locked
(BUG-706/708). Spoken copy bans 相对支持度 (BUG-709).

Task docs assigned 700-704; qizheng already took 700-703.

frontend/src/hooks/use-session-management.ts

@@ -6,6 +6,7 @@ import { useRef } from "react";
 import { showChatNotice as setComposerNotice } from "@/lib/chat-notice";
 import { writeChatSession } from "@/lib/chat-session-write-contract";
 import {
+  SESSION_LOOKUP_FAILED_NOTICE,
   SESSION_MISSING_NOTICE,
   parseSessionUrlQuery,
   writeSessionUrl,
@@ -21,6 +22,7 @@ import {
   fetchSessionDetail,
   fetchSessions,
   LoginRedirectError,
+  lookupSessionById,
   mergeHydratedSession,
   patchSessionModel,
   readSessions,
@@ -405,7 +407,7 @@ export function useSessionManagement(params: SessionManagementParams) {
     const query = parseSessionUrlQuery(search);
     const fallbackId = listed[0]?.id ?? "";
     const requestedId = query.sessionId;
-    if (query.present && (!requestedId || !listed.some((session) => session.id === requestedId))) {
+    if (query.present && !requestedId) {
       writeSessionUrl(null, "replace");
       sessionSelectionSource.current = "history";
       if (fallbackId) selectSession(fallbackId);
@@ -413,6 +415,29 @@ export function useSessionManagement(params: SessionManagementParams) {
       setComposerNotice(SESSION_MISSING_NOTICE);
       return;
     }
+    if (query.present && requestedId && !listed.some((session) => session.id === requestedId)) {
+      void lookupSessionById(requestedId, modelCatalog).then((looked) => {
+        if (looked.status === "found") {
+          setSessions((current) => mergeHydratedSession(current, looked.session));
+          sessionSelectionSource.current = "history";
+          selectSession(looked.session.id);
+          return;
+        }
+        if (looked.status === "missing") {
+          writeSessionUrl(null, "replace");
+          sessionSelectionSource.current = "history";
+          if (fallbackId) selectSession(fallbackId);
+          else setActiveSessionId("");
+          setComposerNotice(SESSION_MISSING_NOTICE);
+          return;
+        }
+        setComposerNotice(SESSION_LOOKUP_FAILED_NOTICE);
+      }).catch((caught) => {
+        if (caught instanceof LoginRedirectError) return;
+        setComposerNotice(SESSION_LOOKUP_FAILED_NOTICE);
+      });
+      return;
+    }
     if (!requestedId) {
       if (fallbackId) {
         sessionSelectionSource.current = "history";