fix: avoid rehydrating historical chat images into canvas

components/canvas/CanvasChatPanel.tsx

@@ -1889,6 +1889,7 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
       role: "user",
       parts,
     });
+    hasHydratedHistoryRef.current = true;
 
     pendingLaunchRef.current = null;
     setInput("");
@@ -1919,6 +1920,12 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
     if (loadedHistorySignatureRef.current === signature) return;
 
     loadedHistorySignatureRef.current = signature;
+    processedMessageIds.current = new Set(
+      historyMessages
+        .filter((message) => message.role === "assistant")
+        .map((message) => message.id)
+    );
+    hasHydratedHistoryRef.current = true;
     setMessages(historyMessages);
     setMessageViewportKey((prev) => prev + 1);
     console.log("[CanvasChat] 已同步历史消息:", historyMessages.length, signature);
@@ -1939,14 +1946,14 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
   }, [historyData, rawChatId, setMessages, status]);
 
   // 监听消息变化，提取图片并添加到画布
-  // 只处理新生成的图片，不处理历史消息中的图片
+  // 仅处理历史同步后的新消息，避免刷新后把历史图片重复回灌到画布
   const processedMessageIds = useRef<Set<string>>(new Set());
-  const isInitialLoad = useRef(true);
+  const hasHydratedHistoryRef = useRef(false);
 
   useEffect(() => {
     loadedHistorySignatureRef.current = "";
     processedMessageIds.current.clear();
-    isInitialLoad.current = true;
+    hasHydratedHistoryRef.current = false;
     hiddenPromptRef.current = null;
     autoContextRef.current = null;
     pendingLaunchRef.current = null;
@@ -2004,18 +2011,8 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
   }, [activeChatId, messages]);
   
   useEffect(() => {
-    // 首次加载历史消息时，只记录已处理的消息 ID，不添加图片到画布
-    // （画布数据应该从 canvasData 中加载，而不是从消息中提取）
-    if (isInitialLoad.current) {
-      messages.forEach(message => {
-        if (message.role === 'assistant') {
-          processedMessageIds.current.add(message.id);
-        }
-      });
-      isInitialLoad.current = false;
-      return;
-    }
-    
+    if (!hasHydratedHistoryRef.current) return;
+
     // 只处理新消息
     messages.forEach(async (message, messageIndex) => {
       if (message.role === 'assistant' && !processedMessageIds.current.has(message.id)) {
@@ -3548,6 +3545,7 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
       role: "user",
       parts: parts,
     });
+    hasHydratedHistoryRef.current = true;
     
     // 清空状态
     setInput("");