三维设置加箭头阈值，静默处理网格冲突

对话框写回 flow_on_px（二维三维共用），去掉 analysis_grid_mismatch 告警，缩短 UV/形变等工程腔文案并认 source=analysis。已用 pane UI 与 controller 单测验证。

apps/studio/tests/test_scene3d_pane_ui.py

@@ -56,6 +56,7 @@ def test_the_pane_holds_a_legend_and_no_settings(panel):
         panel.housing_check,
         panel.deform_check,
         panel.gain_spin,
+        panel.flow_threshold_spin,
         panel.scale_combo,
         panel.depth_adaptive_check,
         panel.fps_combo,
@@ -106,6 +107,36 @@ def test_adaptive_depth_scale_round_trips_through_the_dialog(panel):
     assert panel.settings().depth_scale_adaptive is False
 
 
+def test_arrow_threshold_round_trips_and_feeds_the_shared_policy(panel):
+    """The threshold the dialog writes is the one both views sample with."""
+    from orisys_app_shared.scene3d.contracts import DisplaySettings
+    from orisys_app_shared.scene3d.visual_policy import policy_for_settings
+
+    panel.apply_settings(
+        DisplaySettings(flow_on_px=0.9, flow_grid_spacing=12, max_arrows=200)
+    )
+    assert panel.flow_threshold_spin.value() == pytest.approx(0.9)
+    settings = panel.settings()
+    assert settings.flow_on_px == pytest.approx(0.9)
+    assert settings.flow_off_px == pytest.approx(0.8)
+    assert settings.flow_grid_spacing == 12
+    assert settings.max_arrows == 200
+    # A colour-scale click must not wipe the held grid or the typed threshold.
+    panel.housing_check.setChecked(True)
+    again = panel.settings()
+    assert again.flow_on_px == pytest.approx(0.9)
+    assert again.flow_grid_spacing == 12
+    assert policy_for_settings(again).flow_on_px == pytest.approx(0.9)
+
+
+def test_source_kind_analysis_uses_its_own_label(panel):
+    """A stored result is not labelled as live acquisition."""
+    panel.set_diagnostics_visible(True)
+    panel.set_source_kind("analysis")
+    assert panel.source_label.text() == t("scene3d.source_analysis")
+    assert panel.source_label.toolTip() == t("scene3d.source_analysis_tip")
+
+
 def test_the_pane_header_offers_the_two_actions(qt_app):
     """A gear and a view reset: the two things that belong to *looking*."""
     from orisys_studio.ui.mesh3d_panel import Mesh3dPanel