Description

When loading Hygon libraries, the code previously assumed that
hygon_spec.origin is always available and directly accessed it to
determine the package path.

However, for namespace packages or certain installation layouts,
importlib.util.find_spec() may return a spec whose origin is None,
causing an exception when accessing Path(hygon_spec.origin).

This PR adds a fallback mechanism:

• Use hygon_spec.origin when available.
• Fall back to hygon_spec.submodule_search_locations when origin is
  None.
• Return gracefully with an error message if neither source can provide
  a valid package path.

This improves compatibility with different Python package layouts and
prevents startup failures when loading Hygon-related libraries.

Fixes # (issue)

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring

Changes

Please list the changes introduced in this PR:

• Add a null check for hygon_spec.origin
• Fall back to hygon_spec.submodule_search_locations[0] when origin is unavailable
• Add explicit error handling when neither origin nor submodule_search_locations can determine the package path
• Prevent crashes caused by Path(None) during Hygon library loading

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes