⚡ bolt: [performance improvement] refactor PhotoCarousel visibility checking

[dttdrv]

💡 What: replaced synchronous getBoundingClientRect() in PhotoCarousel.isInView() with a cached isVisible property updated by an IntersectionObserver.
🎯 Why: previously, getBoundingClientRect() was called on every keydown event (e.g. arrow keys) to check if the carousel was visible. this caused layout thrashing and reduced responsiveness.
📊 Impact: eliminates synchronous layout calculations during high-frequency keydown events, reducing frame drops and improving responsiveness.
🔬 Measurement: verify that pressing arrow keys while the carousel is visible or not visible works correctly without any synchronous layout warnings in devtools.

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PR created automatically by Jules for task 11436224521773904632 started by @dttdrv

[cloudflare-workers-and-pages]

Deploying personal-website with    Cloudflare Pages

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