fix: empty session page

pages/aigc/chat/index.vue

@@ -265,6 +265,12 @@ onMounted(() => {
           <!-- ClientOnly avoids hydrate exception -->
           <ClientOnly>
             <TransitionGroup name="chat-item">
+              <div v-if="chatSessions.length === 0">
+                <div class="text-center text-neutral-400 dark:text-neutral-500 py-4 flex flex-col items-center gap-2">
+                  <Icon name="i-tabler-messages" class="text-2xl" />
+                  <span>没有会话</span>
+                </div>
+              </div>
               <ChatItem
                   v-for="session in chatSessions"
                   :chat-session="session" :key="session.id"
@@ -297,7 +303,8 @@ onMounted(() => {
 
       <Transition name="message" mode="out-in">
         <NewSessionScreen
-            v-if="modals.newSessionScreen"
+            v-if="modals.newSessionScreen || getSessionCopyById(currentSessionId!) === undefined"
+            :non-back="getSessionCopyById(currentSessionId!) === undefined"
             @select="createSession"
             @cancel="modals.newSessionScreen = false"
         />