fix: 删除聊天框图片标签时不再删除画布中的图片

- 修改全局键盘事件处理，增加对 contentEditable 元素的检测
- 在删除图片标签时阻止事件冒泡，防止触发画布的删除操作

app/canvas/[id]/page.tsx

@@ -393,8 +393,14 @@ export default function CanvasEditorPage({ params }: PageProps) {
   // 键盘快捷键
   useEffect(() => {
     const handleKeyDown = (e: KeyboardEvent) => {
-      // 如果正在输入则不触发快捷键
+      // 如果正在输入则不触发快捷键（包括 input、textarea 和 contentEditable 元素）
-      if (e.target instanceof HTMLInputElement || e.target instanceof HTMLTextAreaElement) {
+      const target = e.target as HTMLElement;
+      if (
+        target instanceof HTMLInputElement || 
+        target instanceof HTMLTextAreaElement ||
+        target.isContentEditable ||
+        target.closest('[contenteditable="true"]')
+      ) {
         return;
       }
       

components/canvas/CanvasChatPanel.tsx

@@ -1012,7 +1012,7 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
                   e.preventDefault();
                   handleSend();
                 }
-                // 处理 Backspace 删除图片标签
+                // 处理 Backspace 删除图片标签（只删除聊天框中的标签，不影响画布）
                 if (e.key === 'Backspace') {
                   const selection = window.getSelection();
                   if (selection && selection.rangeCount > 0) {
@@ -1022,6 +1022,7 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
                       const prevSibling = range.startContainer.previousSibling as HTMLElement;
                       if (prevSibling && prevSibling.getAttribute?.('data-attachment-index')) {
                         e.preventDefault();
+                        e.stopPropagation(); // 🆕 阻止事件冒泡，防止触发全局删除
                         const index = parseInt(prevSibling.getAttribute('data-attachment-index') || '0');
                         removeAttachment(index);
                         prevSibling.remove();