Release v26.3.0

Performance

• Viewer state-sync transforms (zoom, scroll, spread, cursor, page mode) no longer
  allocate their lookup arrays on every call — the mode lists are hoisted to module
  constants. These transforms run on each scroll-mode, spread-mode, and zoom change the
  viewer emits back to the component.
• Remounting page overlays (pageOverlayTpl) across already-rendered pages now reuses
  the page element already in hand instead of re-finding it by selector, dropping one
  DOM query per page on long documents.

Internal

• The scroll and spread mode lists now have a single source of truth, so the input
  whitelist and the numeric-to-name index map can no longer drift apart.