fix: 修复图表数据结构嵌套问题

- SSEEvent.visualization() 扁平化数据结构
- chart.data 现在直接是数组，而不是嵌套对象
- 前端 ChartDisplay 可以正确接收 data/xKey/yKeys/title

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: MKY508

apps/api/app/models/chat.py

@@ -79,7 +79,15 @@ def visualization(cls, chart_type: str, chart_data: dict[str, Any]) -> "SSEEvent
         """创建可视化事件"""
         return cls(
             type=SSEEventType.VISUALIZATION,
-            data={"chart": {"type": chart_type, "data": chart_data}},
+            data={
+                "chart": {
+                    "type": chart_type,
+                    "data": chart_data.get("data", []),
+                    "xKey": chart_data.get("xKey"),
+                    "yKeys": chart_data.get("yKeys"),
+                    "title": chart_data.get("title"),
+                }
+            },
         )
 
     @classmethod

apps/api/app/services/gptme_engine.py

@@ -167,15 +167,24 @@ async def _execute_with_litellm(
                 if visualization:
                     yield SSEEvent.visualization(
                         chart_type=visualization.get("type", "bar"),
-                        chart_data=visualization,
+                        chart_data={
+                            "data": visualization.get("data", []),
+                            "xKey": visualization.get("xKey"),
+                            "yKeys": visualization.get("yKeys"),
+                            "title": visualization.get("title"),
+                        },
                     )
             elif data and len(data) > 0:
                 # 如果 AI 没有提供图表配置，使用后备的自动生成逻辑
                 visualization = self._generate_visualization(data, query)
                 if visualization:
                     yield SSEEvent.visualization(
                         chart_type=visualization.get("type", "bar"),
-                        chart_data=visualization.get("data", {}),
+                        chart_data={
+                            "data": visualization.get("data", []),
+                            "xKey": visualization.get("xKey"),
+                            "yKeys": visualization.get("yKeys"),
+                        },
                     )
 
         except Exception as e: