Add tests for image layer, image plane, inventory, saved layout, commands, documentation, manifest, and packaging

- Implement tests for image layer functionality including alpha curve and depth layer behavior.
- Create tests for image plane evaluation and modifier input handling.
- Add tests to verify the saved asset inventory and its persistence.
- Introduce tests for the documentation command to ensure correct project version deployment.
- Validate the extension manifest structure and required permissions.
- Develop tests for the packaging process, ensuring correct platform handling and dependency management.
- Enhance image depth plane group functionality with new split threshold input and surface processing.

pyproject.toml

@@ -27,7 +27,7 @@ dev = [
 
 [project.scripts]
 pack = "tools.pack:main"
-build_node = "tools.nodes.cli:main"
+build_nodes = "tools.nodes.cli:main"
 sync_models = "tools.models.cli:main"
 docs = "tools.docs:main"
 
@@ -37,3 +37,7 @@ build-backend = "hatchling.build"
 
 [tool.hatch.build.targets.wheel]
 packages = ["tools"]
+
+[tool.pytest.ini_options]
+# Keep native asserts: bpy 4.5 can crash at shutdown after assertion rewriting.
+addopts = "--assert=plain"