Composition node between a {@see Ui5DashboardInterface} and the
Tiles/Cards it aggregates.
Identity, title, description are inherited from
{@see Ui5ArtifactInterface}; slot machinery from
{@see SlottableInterface}.
Two typed DTO factories. The group renders as a sap.m.Panel
wrapping a sap.f.GridContainer of child controls. The consumer
authors both DTOs through {@see getPanel()} (header text, expandable,
etc.) and {@see getGridContainer()} (snapToRow, layout breakpoints,
etc.). The framework owns the nesting: it injects [GridContainer]
into Panel.content via {@see Panel::withContent()} and injects the
built child elements into GridContainer.items via
{@see GridContainer::withItems()}. Consumers customise properties on
both controls but cannot reshape that nesting.
Emitter selection is owned by the
{@see \LaravelUi5\Core\Ui5\Dashboard\Contracts\DashboardTransformerInterface} via
instanceof dispatch. See atom ARTIFACT_AS_DTO_FACTORY.md.