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

tests/api/test_routes.py

@@ -22,7 +22,8 @@ def test_submit_cta_backtest():
         token = create_token("admin")
 
         # Mock get_orchestrator to return mock orchestrator
-        with patch("sanguo_api.routes.get_orchestrator") as mock_get_orch:
+        with patch("sanguo_api.routes.get_orchestrator") as mock_get_orch, \
+             patch("sanguo_api.routes.get_strategy_class", return_value=Mock()):
             mock_orch = Mock()
             mock_orch.submit_cta = AsyncMock(return_value="cta_test_123")
             mock_get_orch.return_value = mock_orch
@@ -148,9 +149,13 @@ def test_get_task_result():
         token = create_token("admin")
 
         with patch("sanguo_api.routes.get_orchestrator") as mock_get_orch:
+            from sanguo_backtest.result_store import BacktestResult
             mock_orch = Mock()
-            mock_result = Mock()
-            mock_result.statistics = {"total_trades": 10, "total_return": 0.15}
+            mock_result = BacktestResult(
+                task_id="cta_test_123", type="cta", status="done", strategy="S", symbol="600000",
+                params={}, start="2024-01-01", end="2024-12-31",
+                statistics={"total_trades": 10, "total_return": 0.15},
+            )
             mock_orch.get_result.return_value = mock_result
             mock_get_orch.return_value = mock_orch
 
@@ -205,7 +210,8 @@ def test_submit_optimize_returns_pending():
         app = create_app(db_path=db_path, file_dir=None)
         token = create_token("admin")
 
-        with patch("sanguo_api.routes.get_orchestrator") as mock_get_orch:
+        with patch("sanguo_api.routes.get_orchestrator") as mock_get_orch, \
+             patch("sanguo_api.routes.get_strategy_class", return_value=Mock()):
             mock_orch = Mock()
             mock_orch.submit_optimize = AsyncMock(return_value="opt_test_123")
             mock_get_orch.return_value = mock_orch
@@ -322,7 +328,8 @@ def test_optimize_route_calls_submit(tmp_path):
         client = TestClient(app)
         token = create_token("admin")
 
-        with patch("sanguo_api.routes.get_orchestrator") as m:
+        with patch("sanguo_api.routes.get_orchestrator") as m, \
+             patch("sanguo_api.routes.get_strategy_class", return_value=Mock()):
             orch = Mock()
             orch.submit_optimize = AsyncMock(return_value="opt_1")
             m.return_value = orch