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_model_moge2_onnx.py

@@ -184,11 +184,26 @@ class Moge2OnnxTest(unittest.TestCase):
             "metric_scale": np.array((metric_scale,), dtype=np.float32),
         }
 
+        raw["mask"][0, 0, :4] = [0.0, 0.2, 0.7, 1.0]
         result = self.moge.postprocess(raw)
 
         np.testing.assert_allclose(result["depth"], depth * metric_scale, rtol=1e-3)
         np.testing.assert_allclose(result["points"][..., 2], result["depth"], rtol=1e-5)
-        self.assertTrue(result["mask"].all())
+        np.testing.assert_array_equal(result["mask"], raw["mask"][0])
+
+    def test_postprocess_preserves_mask_for_nonpositive_depth(self):
+        mask = np.array([[[0.2, 0.7], [0.0, 1.0]]], dtype=np.float32)
+        raw = {
+            "points": np.zeros((1, 2, 2, 3), dtype=np.float32),
+            "normal": np.zeros((1, 2, 2, 3), dtype=np.float32),
+            "mask": mask,
+            "metric_scale": np.ones(1, dtype=np.float32),
+        }
+        with patch.object(self.moge, "recover_focal_shift", return_value=(1.0, -1.0)) as recover:
+            result = self.moge.postprocess(raw)
+        np.testing.assert_array_equal(recover.call_args.args[1], mask[0] > 0.5)
+        np.testing.assert_array_equal(result["mask"], mask[0])
+        self.assertTrue((result["depth"] < 0).all())
 
 
 if __name__ == "__main__":