Create/edit form for attribute groups, with the inline attribute/value editor on :edit.

The editor is deliberately event-driven, not one nested changeset form (panel finding): the group's NAME saves through a small form like every other resource, while attributes and values persist immediately per action — add, rename-on-blur, kind change, default star, drag reorder, delete. Each mutation is atomic in the context, so there is no staged tree to lose, and the DOM stays flat no matter how many values a group holds.

One page-level language switch drives everything: with a secondary language active, the same inputs read/write that language's overrides (blank clears the override), with the primary text as placeholder.