Add project configuration and test files in JSON5 format

- Introduced new configuration files for testing, including `default.project.json5`, `client_in_folder`, and others.
- Updated existing project files to use JSON5 format, ensuring consistency across configurations.
- Added new Lua scripts and model files to support various test cases.
- Adjusted snapshot files to align with the new project structure and properties.

assets/project-templates/plugin/default.project.json

@@ -1,6 +0,0 @@
-{
-  "name": "{project_name}",
-  "tree": {
-    "$path": "src"
-  }
-}