Start Heroe carousel on second slide and center active slide

[CySSoO]

Motivation

• Ensure the Her oe (Heroe) slider always starts with the second visible image active while keeping the first image visible and opaque and scrolling one image at a time.

Description

• Template change: set data-start-index to 1 when more than one visible state and mark that slide as is-active in views/templates/hook/prettyblocks/prettyblock_heroe_carousel.tpl so the carousel initially shows image 2 as active while image 1 remains visible.
• JS change: update updateSlides() in views/js/everblock.js to compute slidesPerView from viewportWidth / slideWidth and apply a centerOffset so the active slide is centered in the viewport when possible.
• The offset calculation clamps between 0 and maxOffset to avoid overflowing the track and only runs when slideWidth > 0 to prevent NaN/invalid arithmetic.
• No other interactive behaviors (touch swipe, navigation) were changed; the carousel still advances one slide per navigation action.

Testing

• No automated tests were executed for this change.

---

Codex Task