feat:完成新增会话的，会话记录的聊天模块

src/views/session/sessionManager/index.vue

@@ -238,7 +238,7 @@
                     </a-scrollbar>
                     <div class="bottom">
                         <div class="input">
-                            <a-input v-model="inputMsg" @keydown.enter="sendMessage">
+                            <a-input v-model="inputMsg" @keydown.enter="sendMessage" placeholder="输入您想了解的内容，按Enter发送">
                             <template #suffix>
                                 <icon-send  style="cursor: pointer" @click="sendMessage"/>
                             </template>