fix(types): 修复 CI mypy strict + ruff format 失败

mypy (13 errors → 0):
- portfolio/optimizer: register_optimizer 返回类型改为 Callable 装饰器签名
  (原标注 type[WeightOptimizer] 导致 4 个子类 Too many arguments)
- factor/engine: _datetime_to_int 用 isinstance 收窄替代 object→int 强转
- factor/analysis: 删多余 type:ignore（改由 mypy override 统一处理 scipy）
- backtest/orders, execution: np.sqrt 表达式用 float() 包裹消除 no-any-return
- MyTT.pyi: MACD 签名删除错误的 LOW/HIGH 参数（与 MyTT.py 实际签名对齐）
- pyproject: 新增 scipy mypy override (ignore_missing_imports)

ruff format: 8 个 test 文件格式化

验证: 564 passed, mypy 192 文件零错误, ruff check/format 全绿

tests/unit/test_factor_engine.py

@@ -1,5 +1,6 @@
 # tests/unit/test_factor_engine.py
 """Test FactorEngine."""
+
 from __future__ import annotations
 
 import numpy as np
@@ -23,15 +24,17 @@ def _make_df(n: int = 60, seed: int = 42) -> pd.DataFrame:
     amount = close * vol
 
     dates = pd.date_range("2024-01-01", periods=n, freq="D")
-    return pd.DataFrame({
-        "datetime": dates,
-        "open": open_,
-        "high": high,
-        "low": low,
-        "close": close,
-        "vol": vol,
-        "amount": amount,
-    })
+    return pd.DataFrame(
+        {
+            "datetime": dates,
+            "open": open_,
+            "high": high,
+            "low": low,
+            "close": close,
+            "vol": vol,
+            "amount": amount,
+        }
+    )
 
 
 class _SimpleMomentum(Factor):
@@ -196,6 +199,7 @@ class TestFactorEngineWithBuiltins:
         df = _make_df(200)
 
         from easy_tdx.factor.builtin import list_factors
+
         for f_info in list_factors():
             name = f_info["name"]
             result = engine.compute_single(df, [name])