fix: @mention popover position calculation with requestAnimationFrame

src/pages/chat/components/ChatInput.tsx

@@ -74,12 +74,19 @@ export default function ChatInput(props: {
       console.log('[@mention] matched @ at position:', { atIndex, query });
       if (!query.includes(' ')) {
         setMentionQuery(query);
-        // 计算位置
-        const textarea = e.target;
+        // 计算位置 - 使用 inputRef 获取最新 DOM 位置
+        requestAnimationFrame(() => {
+          const textarea = inputRef.current;
+          if (!textarea) {
+            console.log('[@mention] inputRef.current is null');
+            return;
+          }
           const rect = textarea.getBoundingClientRect();
+          console.log('[@mention] textarea rect:', rect);
           setMentionPos({ top: rect.bottom, left: rect.left + 10 });
           console.log('[@mention] show popover:', { top: rect.bottom, left: rect.left + 10, query });
           setShowMentionPopover(true);
+        });
         return;
       }
     }