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。

shared/tests/test_overlays.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import numpy as np
+import pytest
 from orisys_app_shared.scene3d.overlays import (
     arrow_instances_to_mesh,
     build_flow_overlay,
@@ -10,7 +11,7 @@ from orisys_app_shared.scene3d.overlays import (
     force_visual_strength,
 )
 from orisys_app_shared.scene3d.synthetic import poc_scene
-from orisys_app_shared.scene3d.visual_policy import VisualPolicy, select_flow_samples
+from orisys_app_shared.scene3d.visual_policy import FlowSamples, VisualPolicy, select_flow_samples
 
 
 def test_force_visual_strength_is_capped() -> None:
@@ -58,6 +59,30 @@ def test_flow_and_normal_overlays_on_poc_mapping() -> None:
     assert colors.shape[0] == positions.shape[0]
 
 
+def test_an_inactive_sample_is_a_grey_point_and_an_active_one_is_an_arrow() -> None:
+    assets = poc_scene()
+    mapping = assets.surface_mapping
+    assert mapping is not None
+    samples = FlowSamples(
+        rows=np.asarray([1, 1], dtype=np.int32),
+        cols=np.asarray([1, 2], dtype=np.int32),
+        dx=np.asarray([0.8, 0.0]),
+        dy=np.asarray([0.0, 0.0]),
+        magnitude=np.asarray([1.6, 0.0]),
+        active=np.asarray([True, False]),
+    )
+    arrows, diags = build_flow_overlay(samples, mapping)
+    assert not diags
+    assert int(np.count_nonzero(arrows.lengths > 0.0)) == 1
+    assert int(np.count_nonzero(arrows.lengths < 0.0)) == 1
+    idle = arrows.colors[arrows.lengths < 0.0][0]
+    # Brand idle tint #8A93A6, not a ramp colour.
+    assert idle[0] == pytest.approx(0x8A / 255.0, abs=0.02)
+    assert idle[2] == pytest.approx(0xA6 / 255.0, abs=0.02)
+    positions, _triangles, colors = arrow_instances_to_mesh(arrows)
+    assert positions.shape[0] == colors.shape[0] > 0
+
+
 def test_missing_contact_yields_no_arrow() -> None:
     assets = poc_scene()
     mapping = assets.surface_mapping