feat: Add new Geometry Nodes groups for image relief and shadeless shader

- Implemented the "O Image Relief Plane" Geometry Nodes group to create a fixed-base image relief using depth images and various parameters.
- Created the "O Shadeless" shader node group to display color without scene lighting while preserving shadows and reflections.
- Introduced a preview feature for node groups, allowing for interactive visualization of node arrangements in an HTML format.
- Added a template HTML file for rendering node previews with customizable views and controls.

tests/test_edge_depth.py

@@ -120,13 +120,38 @@ def test_diagonal_pixels_share_a_component():
     assert result.depth[5, 5] == 2
 
 
-def test_invalid_donors_are_excluded():
+@pytest.mark.parametrize("validity", [0.0, 0.2, 0.5])
+def test_invalid_donors_are_excluded(validity):
     frame, alpha = silhouette()
-    frame.depth[10, 12] = 100
-    frame.validity[10, 12] = 0
+    frame.depth[10, 6] = 100
+    frame.validity[10, 6] = validity
     result = extend_edge_depth(frame, alpha)
-    assert result.depth[10, 12] == 2
-    assert result.validity[10, 12] == 0
+    assert result.depth[10, 4] == 2
+    assert result.depth[10, 6] == 100
+    assert result.validity[10, 6] == np.float32(validity)
+
+
+def test_internal_mask_hole_does_not_expand_alpha_repair():
+    frame, alpha = silhouette()
+    frame.depth[9:14, 10:15] = 100
+    frame.validity[9:14, 10:15] = 0
+    original = frame.depth.copy()
+    result = extend_edge_depth(frame, alpha)
+    np.testing.assert_array_equal(result.depth[6:19, 6:20], original[6:19, 6:20])
+    assert result.depth[12, 24] == 2
+
+
+def test_opaque_image_keeps_low_mask_depth():
+    frame = make_frame(np.ones((10, 10)))
+    frame.depth[5, 5] = 100
+    frame.validity[5, 5] = 0
+    assert extend_edge_depth(frame, np.ones((10, 10))) is frame
+
+
+def test_component_without_valid_donors_keeps_its_depth():
+    frame, alpha = silhouette()
+    frame.validity[alpha > 0] = 0
+    assert extend_edge_depth(frame, alpha) is frame
 
 
 def test_local_smoothing_reduces_donor_step_and_preserves_core():
@@ -159,16 +184,16 @@ def test_alpha_resize_retains_threshold_values(tmp_path):
 
 
 @pytest.mark.parametrize(
-    "generate_depth,normal_mode,correct",
+    "generate_depth,normal_mode",
     [
-        (True, "OBJECT", True),
-        (True, "TANGENT", True),
-        (True, "TANGENT", False),
-        (False, "OBJECT", True),
+        (True, "OBJECT"),
+        (True, "TANGENT"),
+        (True, "NONE"),
+        (False, "OBJECT"),
     ],
 )
 def test_artifacts_use_corrected_depth_and_original_normals(
-    tmp_path, generate_depth, normal_mode, correct
+    tmp_path, generate_depth, normal_mode
 ):
     frame, alpha = silhouette()
     rgba = np.full((*alpha.shape, 4), 255, np.uint8)
@@ -197,17 +222,18 @@ def test_artifacts_use_corrected_depth_and_original_normals(
     ):
         artifacts.generate_moge2_artifacts(
             context, {}, path, generate_depth=generate_depth, normal_mode=normal_mode,
-            correct_edge_depth=correct,
         )
-    assert normal.call_args.args[0] is frame
-    assert repair.call_count == int(correct and generate_depth)
+    if normal_mode != "NONE":
+        assert normal.call_args.args[0] is frame
+    else:
+        normal.assert_not_called()
+    assert repair.call_count == int(generate_depth)
     if generate_depth:
         written_frame = depth.call_args.args[0]
+        np.testing.assert_array_equal(depth.call_args.kwargs["alpha"], alpha)
         assert metadata.call_args.args[0] is written_frame
-        if correct:
-            assert written_frame.depth[12, 24] == 2
-        else:
-            assert written_frame is frame
+        assert written_frame.depth[12, 24] == 2
+        assert written_frame.validity is frame.validity
     else:
         metadata.assert_not_called()
         depth.assert_not_called()