Fix carousel explicit tab selection reverting

[cursor]

Bug and Impact

Selecting some Core Areas tabs could visibly revert to a different tab after smooth scrolling settled. Reproduced with headless Chrome: at 480px/640px, clicking AI Penetration Testing ended on Thick Clients; at 1024px, clicking Thick Clients ended on Web3 / Blockchain Security.

Root Cause

The click/keyboard path calls scrollIntoView() to center the selected tab. The carousel scroll listener then treated that programmatic smooth scroll as passive user scrolling, recomputed the active tab from the viewport center, and overwrote the explicit selection.

Fix

Suppress the next debounced scroll-sync callback caused by explicit tab centering, and initialize the carousel without triggering synthetic centering.

Validation

• Reproduced the failure before the fix.
• Chrome click sweep passed across 280, 320, 375, 480, 640, 768, and 1024px for all tabs.
• Keyboard ArrowRight navigation passed at 480 and 1024px.
• Static integrity passed for 5 HTML files, 1 CSS file, 28 local refs, and 2 inline scripts.