fix(chat): 澄清问题卡片 UX 优化 — 去悬空引用 + 默认展开

- 提示词增加 ask_clarification 引用规则，避免 LLM 在文本中生成
  "以下信息"/"比如："等悬空引用短语
- 新增 stripDanglingClarificationRef 前端安全网，当消息包含
  ask_clarification 工具调用时自动移除末尾悬空引用
- 澄清卡片默认展开，让用户直接看到选项无需额外点击

desktop/src/components/ChatArea.tsx

@@ -665,6 +665,28 @@ function stripToolNarration(content: string): string {
   return result || content;
 }
 
+/**
+ * Strip dangling clarification references from text when ask_clarification tool was called.
+ * When the LLM calls ask_clarification, it often ends its text with phrases like
+ * "比如：" / "以下信息" / "以下选项" that reference the tool output — but the tool output
+ * is rendered in a separate ClarificationCard, so these become confusing dead-end sentences.
+ */
+function stripDanglingClarificationRef(text: string, hasClarificationTool: boolean): string {
+  if (!hasClarificationTool || !text) return text;
+  // Match trailing dangling references in Chinese and English
+  const patterns = [
+    /[，,]\s*可以(?:提供以下|告诉我更多细节，)?(?:信息|选项|方向|细节|分类|类型)[：:]\s*$/,
+    /[，,]\s*比如[：:]\s*$/,
+    /[，,]\s*(?:例如|譬如|如以下)[：:]\s*$/,
+    /,\s*(?:for example|such as|like|the following)[：:]?\s*$/i,
+  ];
+  for (const pat of patterns) {
+    const stripped = text.replace(pat, '');
+    if (stripped !== text) return stripped;
+  }
+  return text;
+}
+
 function MessageBubble({ message, onRetry }: { message: Message; setInput?: (text: string) => void; onRetry?: () => void }) {
   if (message.role === 'tool') {
     return null;
@@ -749,7 +771,10 @@ function MessageBubble({ message, onRetry }: { message: Message; setInput?: (tex
                 ? (isUser
                     ? message.content
                     : <StreamingText
-                        content={stripToolNarration(message.content)}
+                        content={stripDanglingClarificationRef(
+                          stripToolNarration(message.content),
+                          toolCallSteps?.some(s => s.toolName === 'ask_clarification') ?? false,
+                        )}
                         isStreaming={!!message.streaming}
                         className="text-gray-700 dark:text-gray-200"
                       />

desktop/src/components/ai/ToolCallChain.tsx

@@ -166,7 +166,8 @@ interface ToolStepRowProps {
 }
 
 function ToolStepRow({ step, isActive, showConnector }: ToolStepRowProps) {
-  const [expanded, setExpanded] = useState(false);
+  // Clarification cards default to expanded so users see options immediately
+  const [expanded, setExpanded] = useState(step.toolName === 'ask_clarification');
   const Icon = getToolIcon(step.toolName);
   const label = getToolLabel(step.toolName);
   const isRunning = step.status === 'running';