三维未激活采样显示灰点，二维增加深度叠箭头。

分析对话框默认使用传感器对话框保存的标定，关闭按钮改为保存。框选曲线时数值卡片仍显示光标读数。相关单测通过。

apps/studio/tests/test_scene3d_overlays.py

@@ -120,9 +120,9 @@ def test_2d_3d_flow_sample_points_match() -> None:
         composed = composer.compose(
             assets, _depth_frame(assets, flow=flow), settings
         )
-        arrows_3d = (
-            0 if composed.flow_arrows is None else int(composed.flow_arrows.origins.shape[0])
-        )
+        arrows = None if composed.flow_arrows is None else composed.flow_arrows.lengths
+        # Positive lengths are arrows. Negative lengths are the idle points.
+        arrows_3d = 0 if arrows is None else int(np.count_nonzero(arrows > 0.0))
         # Exactly what the 2D canvas draws from: ``draw_arrow_display`` calls
         # ``select_flow_samples`` with the policy the window passes it, and draws the
         # samples the flag marks active.