Resolved paginator configuration. Three required sub-trees - accessible-name
strings, live-region announcement phrasing, and data-readout formatters -
plus a flat pageSizeOptions list and an optional templates slot tree,
each merged independently by the reducer in
provideCngxPaginatorConfig.
Default items-per-page choices the cngx-pgn-page-size dropdown renders
when no per-instance [options] is bound. The instance input still wins
when it is non-empty; this is the cascade fallback so the segment needs no
boilerplate. Replaced wholesale (not merged) by
withPaginatorPageSizeOptions - a size list is one atomic value.