Add delete for closed trade records.

Only closed groups can be removed from local history; equity is unchanged.

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

backend/app/api/trades.py

@@ -190,3 +190,46 @@ async def group_detail(
         "fills": [_row(x) for x in fills],
         "pnl_summary": gr.get("pnl_summary"),
     }
+
+
+@router.delete("/groups/{group_id}")
+async def delete_group(
+    group_id: str, _user: Annotated[str, Depends(require_user)]
+) -> dict:
+    """删除一条已平仓交易记录（组/成交/残留/相关账本流水）。不回滚权益。"""
+    db = get_db()
+    g = db.fetchone("SELECT * FROM groups WHERE group_id=?", (group_id,))
+    if g is None:
+        raise HTTPException(status_code=404, detail="group not found")
+    status = str(g["status"] or "").lower()
+    if status != "closed":
+        raise HTTPException(
+            status_code=409,
+            detail="只能删除已平仓记录；持仓中或开仓中的组不可删",
+        )
+    pos = db.fetchone("SELECT group_id FROM positions WHERE id=1")
+    if pos and str(pos["group_id"] or "") == group_id:
+        raise HTTPException(
+            status_code=409,
+            detail="当前持仓仍引用该组，不可删除",
+        )
+    with db._lock:
+        db._conn.execute("DELETE FROM fills WHERE group_id=?", (group_id,))
+        db._conn.execute(
+            "DELETE FROM residual_options WHERE group_id=?", (group_id,)
+        )
+        db._conn.execute(
+            "DELETE FROM ledger_entries WHERE group_id=?", (group_id,)
+        )
+        cur = db._conn.execute(
+            "DELETE FROM groups WHERE group_id=? AND status='closed'",
+            (group_id,),
+        )
+        if cur.rowcount <= 0:
+            db._conn.rollback()
+            raise HTTPException(
+                status_code=409,
+                detail="删除失败：组状态已变更",
+            )
+        db._conn.commit()
+    return {"ok": True, "group_id": group_id}