The hide-timer used to fire on a plain phase==="success" timeout,
regardless of whether the banner was actually on screen — if the
threshold was reached while scrolled away, it could hide itself before
the user ever saw it.
Gates the timer on continuous IntersectionObserver visibility
(useInView, no `once`) instead of a lifetime "ever visible" flag — the
latter flips true as soon as the page loads (the banner sits at the
top), which defeats the purpose entirely. The timer now only runs
while the banner is actually in view, and restarts if the user scrolls
away and back before it completes.
Marco
a560ec9434