Add tools and tests for AnyImage model management and documentation

- Implement sync_models.py for preparing and uploading ONNX artifacts.
- Create build_node.py for building and validating Blender scripts.
- Add docs.py for building and previewing documentation with Mike or MkDocs.
- Introduce model_exports.py for exporting PyTorch models to ONNX format.
- Develop pack.py for packaging the project with dependencies for different platforms.
- Add test_sync_models.py to validate sync_models functionality.
- Add test_tool_commands.py to ensure repository tools have correct command scripts.
- Initialize tools package with __init__.py.

src/anyimage/operators/remove_background.py

@@ -2,7 +2,7 @@ import bpy
 
 from ..properties import BEN2_MODEL_KEY
 from ..runtime import JobOperatorBase
-from .common.ai_job import (
+from ..common.ai_job import (
     require_background_input_path,
     invoke_ai_setup_if_needed,
     production_device,
@@ -10,7 +10,7 @@ from .common.ai_job import (
     require_model,
 )
 
-from .common.image_data import (
+from ..common.image_data import (
     cleanup_image_input,
     default_extract_frames,
     is_image_empty,
@@ -70,7 +70,7 @@ class RemoveImageBackground(bpy.types.Operator):
 
 
 def apply_background_response(result, source_object_name):
-    from .common.image_data import (
+    from ..common.image_data import (
         load_color_result_image,
         replace_empty_image,
         require_image_empty,