Add HEDGE_PO_MODE instance modes with shared sim/live path.

Lock one mode per instance/subaccount, cross-asset BTC option/ETH perp sizing, combo-U exit, and ship docs/tests/audit.

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

lib/hedge_plan/hedge_plan_db.py

@@ -90,6 +90,9 @@ def init_hedge_plan_tables(conn: sqlite3.Connection) -> None:
     # 出场:profit=盈利金额(扣双边费);target=目标位点数
     _ensure_column(conn, "hedge_plans", "exit_mode", "TEXT")
     _ensure_column(conn, "hedge_plans", "profit_target_usdt", "REAL")
+    # 永期实例模式:eth|btc|btc_eth;跨币时 underlying=期权标的,perp_underlying=永续标的
+    _ensure_column(conn, "hedge_plans", "po_mode", "TEXT")
+    _ensure_column(conn, "hedge_plans", "perp_underlying", "TEXT")
     _ensure_column(conn, "hedge_plan_legs", "ct_mult", "REAL")