fix(web): 会话列表合同跟着外壳搬家，无活跃会话不再静默吞发送

四条源码合同改到 (app)/layout 与注册载荷两端对断。列表只剩校正会话时普通输入框锁定，发送会打开校正或给出提示。

frontend/src/app/(app)/page.tsx

@@ -20,7 +20,7 @@ import {
   resolveRectificationEntryAction,
 } from "@/lib/rectification-entry";
 import {
-  dropRectificationStoredPending,
+  composerLocksAsRectification, dropRectificationStoredPending,
   ordinaryComposerPlaceholder,
   rectificationOrdinaryComposerReopen,
 } from "@/lib/rectification-session-composer-guard";
@@ -391,7 +391,7 @@ export default function Home() {
 
   const activeSession = sessions.find((session) => session.id === activeSessionId)
     ?? sessions.find((session) => session.sessionType !== "birth_time_rectification");
-  const activeRectificationSession = activeSession?.sessionType === "birth_time_rectification";
+  const activeRectificationSession = composerLocksAsRectification(activeSession, sessions);
   const rectificationSurfaceOpen = Boolean(activeRectificationSession && activeSession && activeSession.id === rectificationSessionId);
   const rectificationComposerLocked = Boolean(activeRectificationSession && !rectificationSurfaceOpen);
   const rectificationComposerReopen = rectificationOrdinaryComposerReopen({ activeRectificationSession, error: rectificationError, errorSessionId: rectificationErrorSessionId, sessionId: activeSession?.id });
@@ -1745,7 +1745,7 @@ export default function Home() {
           {jumpToLatestVisible && (
             <JumpToLatestButton onClick={conversationAnchor.anchorToLatest} />
           )}
-          {rectificationComposerReopen && activeSession ? <RectificationComposerReopen message={rectificationErrorMessage} onReopen={() => void reopenRectificationSession(activeSession.id)} /> : null}
+          {rectificationComposerReopen ? <RectificationComposerReopen message={rectificationErrorMessage} onReopen={() => void reopenRectificationSession(activeSession?.id || rectificationErrorSessionId || "")} /> : null}
           <ChatComposer
             inputRef={composerInput}
             inputLabel={!profileComplete && onboardingStep === "name" ? "输入你的称呼" : "输入你的问题"}