Generic Collection Blocks And Media Overlay Cards

The builder now includes generic collection blocks, media overlay cards, carousel improvements, button block UI tabs, masthead preset edit links, and theme-level colour scheme handling.

Generic collection blocks

Repeated content patterns that previously needed a custom solution can now be handled by the generic collection block. Editors can display any content collection without asking developers for a one-off block variant.

Design ownership at the theme level

Colour and presentation defaults now have clearer ownership at the theme level rather than being re-specified inside each block. Theme teams can define how collection items look once, and editors work within that design system.