feat(node_assets): add image plane geometry nodes and validation scripts

- Implemented `image_plane.py` to build the Image Plane Geometry Nodes group with customizable parameters for geometry, subdivide, and thickness.
- Created `image_plane_validation.py` to validate the functionality of the image plane, ensuring correct geometry generation and material assignment.
- Developed `material_layers.py` to construct shader node groups for image materials, including depth and normal handling.
- Authored `plane_layouts.py` to define node arrangements for image geometry assets.
- Introduced `shadeless.py` to create a shadeless shader node group that displays color without scene lighting while preserving shadows and reflections.

src/anyimage/server/media/__init__.py

@@ -6,7 +6,6 @@ from .input import (
     check_cancelled,
     collect_images,
     copy_color_images,
-    copy_frames,
     extract_video_frames,
     first_frames,
     input_frames,
@@ -31,7 +30,6 @@ __all__ = (
     "check_cancelled",
     "collect_images",
     "copy_color_images",
-    "copy_frames",
     "extract_video_frames",
     "first_frames",
     "input_frames",