固定 HHD 下采样并标记三轴力单位

避免运行中改变 HHD 测量配置，并明确部分标定时各轴单位。已通过 SDK 与共享层测试。

tests/test_signal_processing.py

@@ -246,24 +246,16 @@ def test_read_info_force_stays_raw_without_calibration_json(monkeypatch):
         sensor.disconnect()
 
 
-def test_configure_hhd_downsample_invalidates_solver_cache():
+def test_hhd_downsample_is_fixed_by_sensor_config():
     sensor = _external_sensor()
     try:
-        sensor._hhd_downsample = 1
-        sensor._Sensor__hhd = object()
-        sensor._hhd_grid_shape = (40, 40)
-        sensor.valid_mask = np.ones((90, 90), dtype=bool)
-        sensor.valid_mask_hhd = sensor.valid_mask
-
-        sensor.configure(hhd_downsample=3)
-        assert sensor._hhd_downsample == 3
-        assert sensor._Sensor__hhd is None
-        assert sensor._hhd_grid_shape is None
-        assert sensor.valid_mask_hhd is not None
-        assert sensor.valid_mask_hhd.shape == (30, 30)
-
-        with pytest.raises(ValueError):
-            sensor.configure(hhd_downsample="nope")
+        configured = sensor._config["tracker"]["hhd_downsample"]
+        assert sensor._hhd_downsample == configured
+        sensor.configure(force_median_window=3)
+        assert sensor._hhd_downsample == configured
+        assert "hhd_downsample" not in sensor.filters_state()["measurement"]
+        with pytest.raises(TypeError):
+            sensor.configure(hhd_downsample=1)
     finally:
         sensor.disconnect()