refactor(ui/user): rename nick to name in LocalUser data structure

[qwqcode]

To ensure consistency in data transmission and interaction across different projects and components, we are unifying the LocalUser data structure by renaming nick to name, changing isAdmin to is_admin, and updating the classname of the user nickname element in the comment box from atk-nick to atk-name (the name attribute has also been modified). This change may impact CSS stylesheets. Additionally, projects dependent on the Artalk front-end client API may be affected. We have renamed the nick and isAdmin fields in the LocalUser type interface and updated nick to name and isAdmin to is_admin in LocalStorage.