fix(backtest): result_id 用 DB 行 id + equity/trades 落 JSON（S1.1+S1.2）

- BacktestResult 加 id；save_result 设 result.id=lastrowid（修 get_result bug）
- runner._on_done 用 result.id（getattr 兜底 FactorReport）
- cta_engine 构建 equity_curve/trades DataFrame；save 传 file_dir
- result_store parquet→JSON（去 pyarrow 依赖，本机/容器都稳）
- 16 tests passed

sanguo_backtest/result_store.py

@@ -22,6 +22,7 @@ class BacktestResult:
     equity_curve: Optional[pd.DataFrame] = None
     trades: Optional[pd.DataFrame] = None
     error_msg: Optional[str] = None
+    id: Optional[int] = None
 
 
 # SQLite schema for backtest stats
@@ -73,12 +74,12 @@ def save_result(result: BacktestResult, db_path: str, file_dir: Optional[str] =
             fdir.mkdir(parents=True, exist_ok=True)
 
             if result.equity_curve is not None and not result.equity_curve.empty:
-                equity_path = str(fdir / f"{result.task_id}_equity.parquet")
-                result.equity_curve.to_parquet(equity_path)
+                equity_path = str(fdir / f"{result.task_id}_equity.json")
+                result.equity_curve.to_json(equity_path, orient="records", date_format="iso", force_ascii=False)
 
             if result.trades is not None and not result.trades.empty:
-                trades_path = str(fdir / f"{result.task_id}_trades.parquet")
-                result.trades.to_parquet(trades_path)
+                trades_path = str(fdir / f"{result.task_id}_trades.json")
+                result.trades.to_json(trades_path, orient="records", date_format="iso", force_ascii=False)
 
         # Insert record into database
         cur = conn.execute(
@@ -102,6 +103,7 @@ def save_result(result: BacktestResult, db_path: str, file_dir: Optional[str] =
             )
         )
         conn.commit()
+        result.id = cur.lastrowid
         return cur.lastrowid
     finally:
         conn.close()
@@ -131,9 +133,9 @@ def load_result(rid: int, db_path: str) -> BacktestResult:
         cols = [d[0] for d in conn.execute("SELECT * FROM backtest_stats LIMIT 0").description]
         d = dict(zip(cols, row))
 
-        # Load parquet files if paths exist
-        equity = pd.read_parquet(d["equity_path"]) if d.get("equity_path") else None
-        trades = pd.read_parquet(d["trades_path"]) if d.get("trades_path") else None
+        # Load JSON files if paths exist (equity_curve/trades persisted as JSON)
+        equity = pd.read_json(d["equity_path"], orient="records") if d.get("equity_path") else None
+        trades = pd.read_json(d["trades_path"], orient="records") if d.get("trades_path") else None
 
         return BacktestResult(
             task_id=d["task_id"],