Fix Show actual type in strands hook error messages

[Anshumancanrock]

Resolves #8444

Changes:

• Fixed bug: retNode.baseType → returnedNode.baseType (was causing "undefined" instead of actual type)
• Error messages now show the actual returned type (e.g., "vec4" instead of "undefined")
• Struct mismatch error now lists expected properties so users know what the struct contains
• Added guidance explaining users should modify and return the input struct
• Improved incomplete struct error to show expected vs received properties

PR Checklist

• npm run lint passes
• Inline reference is included / updated
• Unit tests are included / updated

[davepagurek]

Thanks for taking this on! Would you be able to add some unit tests for this? A strategy could be to spy on FES.userError (search for spy in the tests directory for examples) and assert that it was called with the expected message.

[Anshumancanrock]

@davepagurek Done! Added unit tests with vi.mock on strands_FES , covers all three error paths (wrong type in struct hook, vector dimension mismatch, incomplete struct).

Please take a look and let me know if you would like any changes. Thanks !