Add new functionality for image rectification and depth metadata handling

- Implemented a preview tool for rectifying images with interactive aspect controls in `preview.py`.
- Added tests for depth metadata loading to ensure consistent schema usage in `test_depth_metadata.py`.
- Developed comprehensive tests for cutout calibration processes in `test_cutout_calibration.py`, including stability checks and depth calibration.
- Created tests for frame compositing operations in `test_frame_compositing.py`, ensuring correct handling of depth and transparency.
- Introduced material slot inheritance functionality in `material_slots.py` to manage geometry material assignments.
- Built shared shader nodes for material processing in `shader.py`, including roughness and bump mapping setups.

tests/anyimage/common/test_depth_metadata.py

@@ -0,0 +1,25 @@
+import json
+
+import numpy as np
+
+from anyimage.common.depth import load_depth_metadata
+
+
+def test_depth_metadata_loader_uses_one_schema_for_plane_and_cutout(tmp_path):
+    path = tmp_path / "depth.json"
+    path.write_text(
+        json.dumps(
+            {
+                "image_size": [3, 2],
+                "intrinsics": np.eye(3).tolist(),
+                "reference_depth": 1.0,
+            }
+        ),
+        encoding="utf-8",
+    )
+
+    metadata = load_depth_metadata(path)
+
+    assert metadata["image_size"] == (3, 2)
+    assert metadata["intrinsics"] == ((1.0, 0.0, 0.0), (0.0, 1.0, 0.0), (0.0, 0.0, 1.0))
+    assert metadata["reference_depth"] == 1.0