使用push2 数据接口，优化代码

backend/services/tencent.py

@@ -192,10 +192,13 @@ async def fetch_quote(code: str) -> Optional[dict]:
 
 
 async def fetch_history(code: str, days: int = 90) -> List[dict]:
-    """获取历史K线（前复权日K），主数据源"""
+    """获取历史K线（前复权日K），含涨跌幅
+
+    多请求1天以计算第一条的涨跌幅，最终只返回 days 条。
+    """
     market = get_market_prefix(code)
     stock_code = f"{market}{code}"
-    url = f"https://web.ifzq.gtimg.cn/appstock/app/fqkline/get?param={stock_code},day,,,{days},qfq"
+    url = f"https://web.ifzq.gtimg.cn/appstock/app/fqkline/get?param={stock_code},day,,,{days + 1},qfq"
     headers = {
         "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36",
         "Referer": "https://stockapp.finance.qq.com/",
@@ -212,17 +215,31 @@ async def fetch_history(code: str, days: int = 90) -> List[dict]:
             if not isinstance(raw, list):
                 return []
             result = []
+            prev_close = 0
             for record in raw:
                 if not isinstance(record, list) or len(record) < 6:
                     continue
+                close = float(record[2]) if record[2] else 0
+                change_pct = 0
+                if prev_close > 0:
+                    change_pct = (close - prev_close) / prev_close * 100
                 result.append({
                     "date": record[0],
                     "open": float(record[1]) if record[1] else 0,
-                    "close": float(record[2]) if record[2] else 0,
+                    "close": close,
                     "high": float(record[3]) if record[3] else 0,
                     "low": float(record[4]) if record[4] else 0,
-                    "volume": int(record[5]) if record[5] else 0,
+                    "volume": int(float(record[5])) if record[5] else 0,
+                    "changePercent": round(change_pct, 2),
                 })
+                prev_close = close
+
+            # 丢弃最旧1条（它的 prev_close=0 导致涨跌幅为0），只保留最新 days 条
+            if len(result) > 1:
+                result = result[1:]
+            if len(result) > days:
+                result = result[-days:]
+
             return result
         except Exception:
             return []