## What changed
Use `EnvironmentAccess` for skill discovery, environment skill loading, and plugin namespace resolution, replacing direct `ExecutorFileSystem` calls with explicit `None` sandbox arguments.
Wrap existing host and executor filesystems with `FileSystemEnvironmentAccessor::unrestricted` to preserve their current access behavior. Update discovery, loading, and namespace tests to use the same adapter.
GitOrigin-RevId: d68168cc0ee19dc303ef4ee726cf1de1a8db81e0
47fc8d661e