feat(s3): 历史任务 + 参数优化端到端跑通

- result_store.load_result_by_task_id + orchestrator.get_result DB 兜底（历史回看）
- GET /task 列表、GET /task/{id}/optimization-results
- Task.raw_result 存优化结果 list（内存）
- cta_optimizer 修同款 bug（interval d / capital 1M / vnpy DB SETTINGS）
- get_status 返回 error_msg（str 守卫）
- 前端 优化页（网格输入+轮询+结果表）、历史页（任务列表+回看）、侧栏子菜单
- 修 5 个旧 test_routes 回归；73 tests passed
- 冒烟：历史 3 任务 + 优化 9 组合

sanguo_api/routes.py

@@ -120,7 +120,7 @@ def get_status(task_id: str):
         "task_id": task_id,
         "status": s.value if hasattr(s, "value") else str(s),
         "stage": stage or "",
-        "error_msg": task.error_msg if task else None,
+        "error_msg": task.error_msg if (task and isinstance(task.error_msg, str)) else None,
     }
 
 
@@ -266,4 +266,44 @@ def factor_report(task_id: str, factor: str, token: str = Query(...)):
     path = paths.get(factor)
     if not path or not os.path.exists(path):
         raise HTTPException(status_code=404, detail=f"report for {factor} not found")
-    return FileResponse(path)
+    return FileResponse(path)
+
+
+# ===== History + Optimization endpoints (S3) =====
+
+@router.get("/task", dependencies=[Depends(verify_token)])
+def list_tasks(type: str | None = None, status: str | None = None):
+    """List historical tasks (from the results DB)."""
+    from sanguo_backtest.result_store import list_results
+    orch = get_orchestrator()
+    items = []
+    for r in list_results(type_filter=type, db_path=orch.db_path):
+        if status and r.status != status:
+            continue
+        items.append({
+            "id": r.id,
+            "task_id": r.task_id,
+            "type": r.type,
+            "status": r.status,
+            "strategy": r.strategy,
+            "symbol": r.symbol,
+            "start": r.start,
+            "end": r.end,
+        })
+    items.reverse()  # newest first
+    return {"tasks": items}
+
+
+@router.get("/task/{task_id}/optimization-results", dependencies=[Depends(verify_token)])
+def optimization_results(task_id: str):
+    """Optimization results: list of {params, statistics} per parameter combo."""
+    raw = get_orchestrator().get_raw_result(task_id)
+    if raw is None:
+        raise HTTPException(status_code=404, detail="optimization results not ready")
+    rows = []
+    for r in (raw if isinstance(raw, list) else [raw]):
+        rows.append({
+            "params": getattr(r, "params", {}),
+            "statistics": getattr(r, "statistics", {}),
+        })
+    return {"task_id": task_id, "results": rows}