feat: pc端的智能问答页面中，输入框中按回车发送

frontend/src/views/ChatView.vue

@@ -84,6 +84,15 @@ async function submit() {
   }
 }
 
+function onComposerKeydown(e) {
+  if (e.key !== 'Enter') return
+  if (e.shiftKey || e.ctrlKey || e.metaKey || e.altKey) return
+  if (e.isComposing || e.keyCode === 229) return
+  e.preventDefault()
+  if (streaming.value) return
+  submit()
+}
+
 async function onCreateSession() {
   try {
     await createSession()
@@ -349,6 +358,7 @@ watch(messages, scrollToEnd, { deep: true })
             rows="2"
             placeholder="输入问题，或上传图片/文件，AI 将为您解答..."
             :disabled="streaming"
+            @keydown="onComposerKeydown"
           />
           <div class="composer-row">
             <div class="composer-chips">