Two consistency wins from the screenshot/DS audit pass.
Sync icon button now renders DS::Button (variant: icon, size: sm)
instead of a hand-rolled `button_to`. Same component used by other
icon-only actions across the app (settings/profiles, layouts/imports).
Visual delta: 28×28 → 32×32 (DS sm size). Accept the +4px for
consistency. `event.stopPropagation()` still wired via the form opt
so the row's <details> doesn't toggle when the user clicks the
button.
Group heading now follows the established Sure section-label style
(`text-xs font-medium text-secondary uppercase`) used by
`_settings_nav` and the imports/categories surfaces. The previous
sentence-case `text-sm text-primary` was a one-off that didn't
match the rest of the app. Locale strings stay sentence-case;
uppercase comes from CSS `text-transform`. Tests updated to
case-insensitively match the rendered heading text.
ee798aed9e