feat: 优化情景切换功能

frontend/src/components/ChatPanel/index.tsx

@@ -106,6 +106,21 @@ export function ChatPanel({
   return (
     <div className="chat-panel">
       <div className="chat-panel__messages" ref={containerRef}>
+        {/* 情景提示卡片（非空状态 + 非自由对话） */}
+        {messages.length > 0 && !isFreeChat && (
+          <div className="chat-panel__scenario-hint">
+            <div className="scenario-hint-card">
+              <span className="scenario-hint-card__icon">
+                {scenarios.find(s => s.id === activeScenario)?.icon}
+              </span>
+              <div className="scenario-hint-card__text">
+                <strong>{t(scenarios.find(s => s.id === activeScenario)?.nameKey || "")}</strong>
+                <p>{t(`scenario.${activeScenario}.hint`)}</p>
+              </div>
+            </div>
+          </div>
+        )}
+
         {/* 空状态：情景选择 + 场景卡片 */}
         {isEmpty && (
           <div className="chat-panel__welcome">