Harden strategy SoT: fail-closed funds gate, shared open pipeline, LIVE switch guards.

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

backend/app/api/sim.py

@@ -105,41 +105,15 @@ async def sim_open_group(
 
     wkey = window_key()
     db = get_db()
-    from ..strategy.risk_sizing import apply_risk_sizing_to_ledger
+    from ..strategy.open_pipeline import size_and_gate
 
-    rs = apply_risk_sizing_to_ledger(
+    prep = size_and_gate(
         index_px=float(pick.underlying_px),
         option_ask=sizing_ask,
         db=db,
     )
-    if not rs.ok:
-        raise HTTPException(status_code=409, detail=rs.detail)
-
-    try:
-        from ..strategy.auto_usdc import ensure_okx_trading_usdc
-
-        ensure_okx_trading_usdc(db)
-    except Exception:
-        pass
-
-    try:
-        from ..strategy.open_capacity import assess_open_capacity
-
-        cap = assess_open_capacity(db)
-        if cap.get("perp_can_open") is False or cap.get("option_can_open") is False:
-            detail = (
-                f"{cap.get('perp_label')} · {cap.get('option_label')}；"
-                f"永续需≈{cap.get('perp_need_usdt')}U/有{cap.get('perp_have_usdt')}U，"
-                f"期权需≈{cap.get('option_need_usdc')}U/有{cap.get('option_have_usdc')}U"
-            )
-            raise HTTPException(
-                status_code=409,
-                detail=f"资金不足，暂不可开新仓：{detail}",
-            )
-    except HTTPException:
-        raise
-    except Exception:
-        pass
+    if not prep.ok:
+        raise HTTPException(status_code=409, detail=prep.detail)
 
     count = len(
         db.fetchall("SELECT group_id FROM groups WHERE group_id LIKE ?", (f"G-{wkey}-%",))