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"}

frontend/src/hooks/use-consultation-run.ts

@@ -64,6 +64,7 @@ import { completedOnboardingTranscript, isProfileComplete, selectedBirthPlace }
 import { pendingConsultationStorageKey, timestamp } from "@/lib/home-types";
 import {
   consultSendBlockedByRectificationSession,
+  missingActiveSessionSendAction,
   SESSION_NOT_CONSULTATION_CODE,
 } from "@/lib/rectification-session-composer-guard";
 import type {
@@ -514,7 +515,19 @@ export function useConsultationRun(params: ConsultationRunParams) {
       ? sessions.find((session) => session.id === targetSessionId)
       : activeSession;
     const currentSession = options.sessionOverride ?? liveSession;
-    if (!question || !currentSession || !modelCatalog || !account) return false;
+    if (!question) return false;
+    if (!currentSession) {
+      const action = missingActiveSessionSendAction(sessions);
+      if ("openSessionId" in action) {
+        setDraft(originalQuestion);
+        await openRectificationSession(action.openSessionId);
+        setDraft(originalQuestion);
+        return false;
+      }
+      setComposerNotice(action.notice);
+      return false;
+    }
+    if (!modelCatalog || !account) return false;
     if (consultSendBlockedByRectificationSession(currentSession)) {
       if (resuming) {
         pendingConsultation.current = null;

frontend/src/lib/rectification-session-composer-guard.ts

@@ -23,6 +23,24 @@ export function consultSendBlockedByRectificationSession(
   return isRectificationChatSession(session);
 }
 
+/** Empty active session with only rectification rows still occupies the ordinary composer. */
+export function composerLocksAsRectification(
+  activeSession: { sessionType?: string } | null | undefined,
+  sessions: readonly { sessionType: string }[],
+): boolean {
+  if (isRectificationChatSession(activeSession)) return true;
+  if (activeSession) return false;
+  return sessions.some((session) => session.sessionType === "birth_time_rectification");
+}
+
+export function missingActiveSessionSendAction(
+  sessions: readonly { id: string; sessionType: string }[],
+): { openSessionId: string } | { notice: string } {
+  const rectification = sessions.find((session) => session.sessionType === "birth_time_rectification");
+  if (rectification) return { openSessionId: rectification.id };
+  return { notice: "请先选一条对话，或点上方「新建对话」。" };
+}
+
 export function dropRectificationStoredPending<
   S extends { sessionId: string },
   T extends { id: string; sessionType: string },
@@ -63,5 +81,6 @@ export function rectificationOrdinaryComposerReopen(input: {
   if (!input.activeRectificationSession || !input.error || input.error === "profile_incomplete") {
     return false;
   }
+  if (!input.sessionId) return true;
   return !input.errorSessionId || input.errorSessionId === input.sessionId;
 }