feat: explain local surface residuals

tests/test_lidar_local_surface.py

@@ -173,12 +173,24 @@ def test_k1_local_surface_is_dynamic_source_bound_and_read_only(
         assert temporal["step_candidates"]["is_ground_truth"] is False
         assert temporal["step_candidates"]["frames_with_candidates"] > 0
         assert detail["valid"] is True
+        assert detail["surface"]["local_radius_m"] == 5.0
         assert 1.2 < detail["surface"]["sensor_height_m"] < 1.6
         assert detail["counts"]["surface"] > 50
         assert detail["counts"]["occupied"] > 0
         assert detail["counts"]["step_candidate"] > 0
         assert detail["prediction"]["current_frame_excluded"] is True
         assert detail["prediction"]["available"] is True
+        evidence = detail["prediction"]["evidence"]
+        assert evidence["available"] is True
+        assert evidence["current_frame_excluded_from_plane"] is True
+        assert evidence["basis"] == "current-lower-cell-observations"
+        assert evidence["ground_truth"] is False
+        assert len(evidence["cell_points_xyz_m"]) == detail["prediction"]["cell_count"]
+        assert len(evidence["cell_signed_residual_m"]) == detail["prediction"]["cell_count"]
+        assert len(evidence["cell_inlier"]) == detail["prediction"]["cell_count"]
+        assert sum(evidence["cell_inlier"]) / detail["prediction"]["cell_count"] == (
+            detail["prediction"]["inlier_fraction"]
+        )
         assert detail["temporal"]["compared"] is True
         assert detail["authority"]["commands_enabled"] is False
         assert review["available"] is True