fix(chat): 修复重连后对话状态丢失导致消息发送失败的问题

在 WebSocket 重连场景下，服务端可能丢失 `conversationId` 状态，导致后续消息发送被拒绝。通过在客户端消息中携带 `conversationId`，并在服务端添加 fallback 恢复逻辑，确保重连后仍能正常发送消息。

同时优化了 `pendingMessage` 类型定义，支持存储待发送的图片附件，修复了延迟发送场景下图片丢失的问题。

web/client/src/components/chat/ChatInput.tsx

@@ -75,7 +75,7 @@ export function ChatInput({ onSend, disabled, connecting }: { onSend: (content:
   const handleSend = () => {
     const text = input.trim();
     if ((!text && images.length === 0) || disabled) return;
-    const imgs = images.length > 0 ? images.map(({ data, mimeType }) => ({ data, mimeType })) : undefined;
+    const imgs = images.length > 0 ? images.map(({ data, mimeType }) => ({ type: 'image' as const, data, mimeType })) : undefined;
     onSend(text || '(图片)', imgs);
     setInput('');
     setImages([]);

web/client/src/components/chat/ChatView.tsx

@@ -19,7 +19,7 @@ export function ChatView() {
   const [manifestPath, setManifestPath] = useState<string | null>(null);
   const [accounts, setAccounts] = useState<Account[]>([]);
   const [quote, setQuote] = useState<string | null>(null);
-  const [pendingMessage, setPendingMessage] = useState<string | null>(null);
+  const [pendingMessage, setPendingMessage] = useState<{ content: string; images?: Array<{ type: 'image'; data: string; mimeType: string }> } | null>(null);
   const [showScrollBtn, setShowScrollBtn] = useState(false);
   const creatingRef = useRef(false);
   const scrollRef = useRef<HTMLDivElement>(null);
@@ -72,7 +72,7 @@ export function ChatView() {
   useEffect(() => {
     if (conversationId && connected && pendingMessage) {
       const timer = setTimeout(() => {
-        send(pendingMessage);
+        send(pendingMessage.content, pendingMessage.images);
         setPendingMessage(null);
       }, 300);
       return () => clearTimeout(timer);
@@ -108,10 +108,10 @@ export function ChatView() {
   }, [removeMessage]);
 
   // Delayed conversation creation
-  const handleSendNew = useCallback(async (content: string) => {
+  const handleSendNew = useCallback(async (content: string, images?: Array<{ data: string; mimeType: string }>) => {
     if (creatingRef.current) return;
     creatingRef.current = true;
-    setPendingMessage(content);
+    setPendingMessage({ content, images });
 
     try {
       const newId = await createConversation(content.slice(0, 30), selectedAccountId || undefined);
@@ -131,7 +131,7 @@ export function ChatView() {
     if (conversationId) {
       send(content, images);
     } else {
-      handleSendNew(content);
+      handleSendNew(content, images);
     }
   }, [send, quote, conversationId]);
 

web/client/src/hooks/useChat.ts

@@ -156,8 +156,9 @@ export function useChat(conversationId: string | null) {
     }
   }, [conversationId, connected]);
 
-  const send = useCallback((content: string, images?: Array<{ data: string; mimeType: string }>) => {
-    chatSocket.send('chat', { content, images });
+  const send = useCallback((content: string, images?: Array<{ type: 'image'; data: string; mimeType: string }>) => {
+    const convId = activeConvRef.current;
+    chatSocket.send('chat', { content, images, conversationId: convId });
   }, []);
 
   const stop = useCallback(() => {

web/server/ws/chat.ts

@@ -30,6 +30,10 @@ export function handleChat(ws: WebSocket) {
       }
 
       if (msg.type === 'chat') {
+        // Fallback: use conversationId from message if server state lost (e.g. after reconnect)
+        if (!conversationId && msg.conversationId) {
+          conversationId = msg.conversationId as string;
+        }
         if (!conversationId) {
           ws.send(JSON.stringify({ type: 'error', data: { message: '没有活跃对话，请先创建或选择一个对话' } }));
           return;