feat: chat login

pages/aigc/chat/index.vue

@@ -302,8 +302,18 @@ onMounted(() => {
     <div class="h-[calc(100vh-4rem)] flex-1 bg-white dark:bg-neutral-900">
 
       <Transition name="message" mode="out-in">
+        <div v-if="!loginState.is_logged_in" class="w-full h-full">
+          <div class="w-full h-full flex flex-col justify-center items-center gap-2 bg-neutral-100 dark:bg-neutral-900">
+            <Icon name="i-tabler-user-circle" class="text-7xl text-neutral-300 dark:text-neutral-700"/>
+            <p class="text-sm text-neutral-500 dark:text-neutral-400">请登录后使用</p>
+            <UButton class="mt-2 font-bold" color="black" variant="solid" size="xs"
+                     @click="modal.open(ModalAuthentication)">
+              登录
+            </UButton>
+          </div>
+        </div>
         <NewSessionScreen
-            v-if="modals.newSessionScreen || getSessionCopyById(currentSessionId!) === undefined"
+            v-else-if="modals.newSessionScreen || getSessionCopyById(currentSessionId!) === undefined"
             :non-back="!getSessionCopyById(currentSessionId!)"
             @select="createSession"
             @cancel="modals.newSessionScreen = false"