Forces the flow onto a new page (a standalone counterpart to SectionNode.breakBefore) — takes no
vertical space; render calls ctx.forcePageBreak(), which is a no-op when the cursor is already at
the top of a page (so it never leaves a blank page). Not allowed inside a confined zone
(row/box/band), where forcePageBreak has no meaning — rejected at build time by
assertConfinedChildAllowed.
Forces the flow onto a new page (a standalone counterpart to SectionNode.breakBefore) — takes no vertical space; render calls ctx.forcePageBreak(), which is a no-op when the cursor is already at the top of a page (so it never leaves a blank page). Not allowed inside a confined zone (row/box/band), where forcePageBreak has no meaning — rejected at build time by assertConfinedChildAllowed.