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/app/globals.css

@@ -3326,24 +3326,6 @@ input:not([type="radio"]):not([type="checkbox"]):not([class^="ant-"]):not([class
 .rectification-range-delivery__accept:disabled {
   cursor: default;
 }
-.rectification-range-delivery__tie-break {
-  justify-self: start;
-  min-height: 44px;
-  padding: 0 12px;
-  border: 1px solid var(--color-border);
-  border-radius: var(--radius-lg);
-  color: var(--color-ink-secondary);
-  background: var(--color-canvas);
-  font: inherit;
-  cursor: pointer;
-}
-.rectification-range-delivery__tie-break:focus-visible {
-  outline: 2px solid var(--color-focus);
-  outline-offset: 2px;
-}
-.rectification-range-delivery__tie-break:disabled {
-  cursor: default;
-}
 .rectification-range-delivery__invite {
   margin: 0;
   color: var(--color-ink);

frontend/src/app/page.tsx

@@ -210,6 +210,7 @@ import {
   LoginRedirectError,
   mergeHydratedSession,
   patchSessionModel,
+  resolveLookupBootstrap,
   payloadCode,
   payloadMessage,
   readSessions,
@@ -993,12 +994,22 @@ export default function Home() {
         }
 
         if (controller.signal.aborted) return;
-        const bootstrapSelection = resolveBootstrapSessionSelection({
+        const listedSelection = resolveBootstrapSessionSelection({
           listedIds: nextSessions.map((session) => session.id),
           defaultSessionId: nextSessions[0].id,
           search: window.location.search,
           storedReturnId: readLoginSessionReturn(),
         });
+        const lookedUp = await resolveLookupBootstrap({
+          selection: listedSelection,
+          sessions: nextSessions,
+          defaultSessionId: nextSessions[0].id,
+          catalog: nextModelCatalog,
+          signal: controller.signal,
+        });
+        if (controller.signal.aborted) return;
+        nextSessions = lookedUp.sessions;
+        const bootstrapSelection = lookedUp.selection;
         let landingSessionId = resolveStarterHomeLandingSessionId(
           nextSessions,
           bootstrapSelection.sessionId,
@@ -1061,6 +1072,8 @@ export default function Home() {
           setComposerNotice("模型服务暂时不可用，当前无法发送问题。");
         } else if (parsedSessions.fallbackSessionIds.length > 0) {
           setComposerNotice("此前选择的模型已下线，已切换为默认模型。");
+        } else if (lookedUp.notice) {
+          setComposerNotice(lookedUp.notice);
         } else if (bootstrapSelection.missing) {
           setComposerNotice(SESSION_MISSING_NOTICE);
         }