fix: 修复连接泄漏、double-put_db、北交所映射缺失

- analysis.py: 6个端点将 put_db(conn) 从 try 移到 finally，异常时不泄漏
- trades.py: 移除 update_trade/delete_trade 中多余的 put_db(conn)，避免 double-put 破坏连接池
- trades.py: stoploss_check 补充北交所(8/9开头)腾讯API代码映射

stock-html/routes/trades.py

@@ -130,7 +130,6 @@ def update_trade(trade_id):
         """, (trade_id, user_id))
         old_trade = cur.fetchone()
         if not old_trade:
-            put_db(conn)
             return jsonify({'error': '交易记录不存在'}), 404
 
         cur.execute("""
@@ -152,7 +151,6 @@ def update_trade(trade_id):
         trade = cur.fetchone()
         if not trade:
             conn.rollback()
-            put_db(conn)
             return jsonify({'error': '交易记录不存在'}), 404
 
         old_delta = _calc_cash_delta(old_trade.get('trade_type'), old_trade.get('price'), old_trade.get('quantity'))
@@ -194,7 +192,6 @@ def delete_trade(trade_id):
         """, (trade_id, user_id))
         old_trade = cur.fetchone()
         if not old_trade:
-            put_db(conn)
             return jsonify({'success': False, 'error': '交易记录不存在'}), 404
 
         cur.execute("DELETE FROM trades WHERE id = %s AND user_id = %s", (trade_id, user_id))
@@ -306,7 +303,7 @@ def check_stoploss():
                     current_price = 0
                     try:
                         import requests as _rq
-                        _tc = ('sh' if code.startswith('6') else 'sz') + code
+                        _tc = ('sh' if code.startswith('6') else 'bj' if code.startswith(('8', '9')) else 'sz') + code
                         _rr = _rq.get(f'http://qt.gtimg.cn/q={_tc}', timeout=5,
                                       headers={'Referer': 'https://finance.qq.com'})
                         if _rr.status_code == 200 and '\"' in _rr.text: