In scrolled mode the ruler's geometry-cache effect re-ran on every
relocate — including those fired continuously while scrolling — and
re-snapped the band to the next line forward from a screen-fixed
anchor, so the band crept down the page as the reader scrolled.
Place the band once on mount (and after a viewport-dimension change),
but never re-snap on a plain scroll relocate. Click-driven snapping
(the reading-ruler-move handler + pendingScrollAlign realign) is
unchanged, and paginated mode is unaffected.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Huang Xin
97191a57c0