Every size up to 36x66 prints on one sheet; 66x66 is two 36x66 sheets glued side by side over 6 in, and 60x96
is three 36x60 sheets stacked over 6 in overlaps. 36x48 moves from legacy into the ladder (3x4ft still
resolves to it); 24x36 stays legacy. check:poster-sizes now also refuses a size that is both offered and
legacy, and a glued size other than 66x66 and 60x96; its self-test refuses 10 broken tables.
library/constants/posterSizes.js gains POSTER_LADDER: five portrait sizes keyed WxH in inches, each with the
sheets a printer feeds (named as panelSheets.js planPanels() takes them), whether a photo slot fits, and how
it reaches paper (the browser's print for paper, a print-shop PDF for the rest). Legacy 24x36 and 36x48
still resolve, older names (3x3ft, 5x8ft, letter, a4...) alias to the ladder, and paperFor() picks Letter
or A4 from a locale's region. The existing map-export presets are unchanged.
check:poster-sizes (gates:pre) audits the table: the order matches the ladder, keys are dot-free, every
size is portrait, the sheets glue up to the finished size, photos on exactly the two large sizes, paths,
aliases and the paper fixtures. Its --self-test refuses 8 broken tables.
