EPIC: Role detail view #565

A detail view for a single role with a Members tab and a Permissions tab, reached by the view/edit action on a table row. Standard roles show an explicit "Duplicate role" button and a read-only multi-role comparison matrix (sibling roles as columns, checkmarks per permission - an existing component, relocated here). Custom roles show an inline pencil to rename, a kebab overflow menu (Duplicate / Delete), a resource pill + last-updated, a banner noting how many members the role is assigned to, and an editable single-role permissions accordion whose changes are saved explicitly (unsaved-changes banner + Save, with a navigate-away guard). Covers the "View a Standard Role" and "View a Custom Role" flows plus assigning, renaming, duplicating and deleting from the detail view.