feat: 前端输入框体验优化

- AI 响应完成后自动聚焦输入框
- 输入框和发送按钮居中对齐
- 隐藏输入框滚动条
- 新建话题无需输入名称，自动生成默认标题

web/src/App.tsx

@@ -142,12 +142,9 @@ function App() {
       return
     }
 
-    const title = prompt('Enter topic title:')
-    if (title) {
-      const cmd = createTopic(title)
+    const cmd = createTopic()
     handleCommand(cmd)
     sendMessage({ type: 'command', payload: JSON.stringify(cmd) })
-    }
   }, [sendMessage, handleCommand, createTopic, sessionId, isReadOnly])
 
   const handleSwitchTopic = useCallback(

web/src/components/Chat/ChatContainer.tsx

@@ -27,6 +27,7 @@ export function ChatContainer({
       <MessageInput
         onSend={onSendMessage}
         disabled={isLoading}
+        isLoading={isLoading}
         isReadOnly={isReadOnly}
         channelName={channelName}
       />

web/src/components/Chat/MessageInput.tsx

@@ -4,6 +4,7 @@ import { useState, useRef, useEffect } from 'react'
 interface MessageInputProps {
   onSend: (content: string) => void
   disabled?: boolean
+  isLoading?: boolean
   placeholder?: string
   isReadOnly?: boolean
   channelName?: string
@@ -12,12 +13,14 @@ interface MessageInputProps {
 export function MessageInput({
   onSend,
   disabled = false,
+  isLoading = false,
   placeholder = '输入消息...按 / 查看命令',
   isReadOnly = false,
   channelName,
 }: MessageInputProps) {
   const [content, setContent] = useState('')
   const textareaRef = useRef<HTMLTextAreaElement>(null)
+  const wasLoadingRef = useRef(false)
 
   useEffect(() => {
     const textarea = textareaRef.current
@@ -27,6 +30,14 @@ export function MessageInput({
     }
   }, [content])
 
+  // 当 isLoading 从 true 变为 false 时，自动聚焦输入框
+  useEffect(() => {
+    if (wasLoadingRef.current && !isLoading && !isReadOnly) {
+      textareaRef.current?.focus()
+    }
+    wasLoadingRef.current = isLoading
+  }, [isLoading, isReadOnly])
+
   const handleSend = () => {
     if (content.trim() && !disabled && !isReadOnly) {
       onSend(content.trim())
@@ -74,8 +85,8 @@ export function MessageInput({
 
   return (
     <div className="border-t border-white/8 bg-[#12121a]/80 backdrop-blur-md p-4">
-      <div className="flex gap-3 items-end max-w-5xl mx-auto">
-        <div className="flex-1 relative">
+      <div className="flex gap-3 items-center max-w-5xl mx-auto">
+        <div className="flex-1 relative flex items-center">
           <textarea
             ref={textareaRef}
             value={content}
@@ -84,14 +95,14 @@ export function MessageInput({
             placeholder={placeholder}
             disabled={disabled}
             rows={1}
-            className="w-full resize-none rounded-xl border border-white/10 bg-[#1a1a25] px-4 py-3 pr-12 text-sm text-white placeholder:text-zinc-500 focus:border-[#00f0ff]/50 focus:outline-none focus:ring-1 focus:ring-[#00f0ff]/20 disabled:opacity-50 transition-all"
+            className="w-full resize-none rounded-xl border border-white/10 bg-[#1a1a25] px-4 py-3 pr-12 text-sm text-white placeholder:text-zinc-500 focus:border-[#00f0ff]/50 focus:outline-none focus:ring-1 focus:ring-[#00f0ff]/20 disabled:opacity-50 transition-all self-center scrollbar-hide"
           />
           <Sparkles className="absolute right-3 top-1/2 -translate-y-1/2 h-4 w-4 text-zinc-600 pointer-events-none" />
         </div>
         <button
           onClick={handleSend}
           disabled={disabled || !content.trim()}
-          className="flex h-10 w-10 items-center justify-center rounded-xl bg-gradient-to-r from-[#00f0ff] to-[#3b82f6] text-white shadow-lg shadow-[#00f0ff]/20 hover:shadow-xl hover:shadow-[#00f0ff]/30 hover:scale-105 disabled:opacity-50 disabled:hover:scale-100 disabled:cursor-not-allowed transition-all"
+          className="flex h-10 w-10 shrink-0 items-center justify-center rounded-xl bg-gradient-to-r from-[#00f0ff] to-[#3b82f6] text-white shadow-lg shadow-[#00f0ff]/20 hover:shadow-xl hover:shadow-[#00f0ff]/30 hover:scale-105 disabled:opacity-50 disabled:hover:scale-100 disabled:cursor-not-allowed transition-all"
         >
           {disabled ? (
             <Loader2 className="h-4 w-4 animate-spin" />

web/src/hooks/useChat.ts

@@ -47,7 +47,7 @@ interface UseChatReturn {
 
   // Topic 方法
   selectTopic: (topicId: string) => void
-  createTopic: (title: string) => Command
+  createTopic: (title?: string) => Command
   switchTopic: (topicId: string) => Command
 
   // 初始化方法
@@ -425,10 +425,10 @@ export function useChat(): UseChatReturn {
     setMessages([])
   }, [])
 
-  const createTopic = useCallback((title: string): Command => {
+  const createTopic = useCallback((title?: string): Command => {
     return {
       type: 'create_session',
-      title,
+      title: title || `话题 ${new Date().toLocaleString('zh-CN', { month: 'short', day: 'numeric', hour: '2-digit', minute: '2-digit' })}`,
     }
   }, [])
 

web/src/index.css

@@ -45,6 +45,16 @@
   background: var(--accent-blue);
 }
 
+/* Hide scrollbar utility */
+.scrollbar-hide {
+  -ms-overflow-style: none;
+  scrollbar-width: none;
+}
+
+.scrollbar-hide::-webkit-scrollbar {
+  display: none;
+}
+
 /* Base styles */
 * {
   box-sizing: border-box;