## button_group (`poetry_button_group`)

Visually joins adjacent buttons and controls into one group.

Class: Poetry::Ui::ButtonGroup::Component - BEM block `poetry-ui-button_group`.
Content block REQUIRED (its member controls) - a blockless call raises.
- `orientation:` (symbol) - one of horizontal|vertical, default "horizontal", required - The join axis - a horizontal row or a vertical stack.
- PART `button-group` - The role=group root - its selectors join ANY data-slot children into the segmented unit | states: data-orientation=horizontal|vertical (the join axis)
- PART `button-group-text` - A non-button member (the poetry_button_group_text helper's div) - a text affix joined like a button
In blocks: `data-index` - for a screen, start from the block (MCP compose/describe_block, or `bin/rails g poetry:block`), not from scratch.
- RULE: Members go in the content block - the group's selectors join ANY data-slot children (buttons, inputs, select triggers); never hand-round the inner corners.
- RULE: Give the group an aria-label when the page has more than one (role=group is unnamed by default).
- RULE: A visual divider between members is poetry_button_group_separator, not a styled border.