顺势加仓 v2：程序监控滚仓、文档页与平仓同步

重写滚仓计仓与四种加仓方式（市价/斐波/突破），程序盯 mark 触价成交；风险读监控单；pending 可删不可改；手动平仓同步结束滚仓。新增 /strategy/roll/docs 说明页与顺势加仓滚仓说明.md。

Co-authored-by: Cursor <cursoragent@cursor.com>

strategy_db.py

@@ -155,6 +155,8 @@ def init_strategy_tables(conn) -> None:
         "ALTER TABLE order_monitors ADD COLUMN key_signal_type TEXT",
         "ALTER TABLE trend_pullback_plans ADD COLUMN leg_fill_prices_json TEXT",
         "ALTER TABLE roll_legs ADD COLUMN stop_offset_pct REAL",
+        "ALTER TABLE roll_legs ADD COLUMN breakthrough_price REAL",
+        "ALTER TABLE roll_legs ADD COLUMN last_mark_price REAL",
     ):
         try:
             conn.execute(ddl)