Replace per-plane pixel_scale/viewing_angle with z_tolerance; split pointing angle

MeasurementPlane now carries a z_tolerance (uniform tolerance mechanism)
instead of the removed pixel_scale/viewing_angle_deg fields.
ReconstructionResult.pointing_angle_deg becomes horizontal/vertical fields
to match the beam's two independent tilt degrees of freedom.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/test_data.py

@@ -10,19 +10,15 @@ def test_measurement_plane_stores_fields():
 
     assert plane.z == 0.3
     assert np.array_equal(plane.flux, flux)
-    assert plane.pixel_scale is None
-    assert plane.viewing_angle_deg is None
+    assert plane.z_tolerance == 0.0
     assert plane.label is None
 
 
 def test_measurement_plane_stores_optional_fields():
     flux = np.ones((4, 4))
-    plane = MeasurementPlane(
-        flux=flux, z=0.4, pixel_scale=0.1, viewing_angle_deg=5.0, label="plane_40cm"
-    )
+    plane = MeasurementPlane(flux=flux, z=0.4, z_tolerance=0.01, label="plane_40cm")
 
-    assert plane.pixel_scale == 0.1
-    assert plane.viewing_angle_deg == 5.0
+    assert plane.z_tolerance == 0.01
     assert plane.label == "plane_40cm"
 
 
@@ -39,6 +35,11 @@ def test_measurement_plane_rejects_non_positive_z():
         MeasurementPlane(flux=np.ones((4, 4)), z=-0.1)
 
 
+def test_measurement_plane_rejects_negative_z_tolerance():
+    with pytest.raises(ValueError, match="z_tolerance"):
+        MeasurementPlane(flux=np.ones((4, 4)), z=0.3, z_tolerance=-0.01)
+
+
 def test_validate_planes_rejects_fewer_than_three():
     planes = [
         MeasurementPlane(flux=np.ones((4, 4)), z=0.3),
@@ -82,12 +83,15 @@ def test_reconstruction_result_stores_fields():
         purity={(0, 0): (1.0, 0.0)},
         reconstructed_field=np.ones((4, 4), dtype=complex),
         centers=[(0.0, 0.0)],
-        pointing_angle_deg=0.0,
-        geometry={"pixel_scale": 0.1, "viewing_angle_deg": 2.0},
+        pointing_angle_horizontal_deg=0.1,
+        pointing_angle_vertical_deg=-0.2,
+        geometry={"focal_length_px": 2000.0},
         residuals=[np.zeros((4, 4))],
         coefficient_uncertainty={(0, 0): 0.01},
         used_phase_retrieval=False,
     )
 
     assert result.purity[(0, 0)] == (1.0, 0.0)
+    assert result.pointing_angle_horizontal_deg == 0.1
+    assert result.pointing_angle_vertical_deg == -0.2
     assert result.used_phase_retrieval is False