⚡ Reduce embla-carousel forced reflow on the homepage

Parent: #4889 · Priority 4 — smallest item, tackle last.

Problem

embla-carousel still appears in the forced-reflow audit:

chunks/6447.…js  →  ~18–26 ms

Its engine measures every slide on init:

measure: function (t) {
  const { offsetTop, offsetLeft, offsetWidth, offsetHeight } = t; ...
}

The homepage mounts two carousels (v3LogoCarousel, v3PeopleCarousel), so both measure during load.

For reference, the same audit previously flagged our own ButtonRow at 21 ms; moving its geometry reads into the ResizeObserver callback removed it from the list entirely (chunk 9148 no longer appears). This issue is the remaining third-party equivalent.

Suggested approach

• Consider deferring carousel init until near-viewport.
• Caveat: naive lazy-mounting risks re-introducing layout shift (see #4890). Any deferral must reserve the carousel's height up front, otherwise we trade TBT for CLS — a bad swap, since CLS is currently the larger scoring loss.

Note

This is inside a third-party library, so the ceiling here is low. Do not start this before #4890 and #4891.

Start by reproducing the forced-reflow audit for the homepage carousels v3LogoCarousel and v3PeopleCarousel, then inspect the embla-carousel initialization and the affected chunks. Any change is done only when the carousel no longer appears in the audit without introducing layout shift; wait until #4890 and #4891 are complete.