Function scrollBy

src/ink/components/ScrollBox.tsx:148–159

(dy: number)

      scrollMutated(box);
    },
    scrollBy(dy: number) {
      const el = domRef.current;
      if (!el) return;
      el.stickyScroll = false;
      // Wheel input cancels any in-flight anchor seek — user override.
      el.scrollAnchor = undefined;
      // Accumulate in pendingScrollDelta; renderer drains it at a capped
      // rate so fast flicks show intermediate frames. Pure accumulator:
      // scroll-up followed by scroll-down naturally cancels.
      el.pendingScrollDelta = (el.pendingScrollDelta ?? 0) + Math.floor(dy);
      scrollMutated(el);
    },
    scrollToBottom() {
      const el = domRef.current;
      if (!el) return;