Italian language support

Hello,

I would like to contribute an Italian translation for ComfyUI.

Italian is not currently available among the supported languages. I am a native Italian speaker and I would be happy to review and improve the translations and help maintain the Italian locale over time.

The proposed locale code is `it`, displayed as `Italiano`.

Could you please confirm that I can proceed with the implementation following the translation contributing guide?

Thank you.

Read the repository's translation contributing guide first, then identify where supported locales are registered and how translations are organized. Add the `it` locale displayed as `Italiano`, and verify that Italian appears among the available languages with its translated content reviewed.

Written by the indexing model from the issue text.