博弈分析按合约分类展示，新增合约下拉选择器

ft-app/app/routers/admin.py

@@ -2,7 +2,7 @@ from fastapi import APIRouter, Depends, Form, Request
 from fastapi.responses import HTMLResponse, RedirectResponse
 from sqlalchemy.orm import Session
 from app.database import get_db
-from app.models import Product, Contract, DailyBar
+from app.models import Product, Contract, DailyBar, PositionSnapshot
 from app.collector import sync_active_contracts, sync_one_contract
 
 router = APIRouter(prefix="/admin", tags=["admin"])
@@ -113,6 +113,7 @@ def delete_contract(contract_id: int, db: Session = Depends(get_db)):
     c = db.query(Contract).filter(Contract.id == contract_id).first()
     if c:
         db.query(DailyBar).filter(DailyBar.contract == c.code).delete()
+        db.query(PositionSnapshot).filter(PositionSnapshot.contract_code == c.code).delete()
         db.delete(c)
         db.commit()
     return RedirectResponse("/admin/?tab=contract", status_code=303)