fix: resolve duplicate testimonial mapping in Testimonial section (#938)

[Pratik-1213]

Changes

Problem

The "Loved by developers" testimonial section on the landing page displayed the same
set of testimonials twice visibly due to a naive array duplication ([...testimonials, ...testimonials])
with a hardcoded translateX(-50%) scroll animation.

Fix

• Added getUniqueTestimonials() helper — deduplicates testimonials by id using a Set,
  preventing any future duplicate data entries from showing up
• Pixel-based scroll calculation — uses useRef + useEffect to measure the exact pixel
  width of one set of testimonials, then scrolls by that exact amount instead of a hardcoded 50%.
  This ensures the infinite loop resets seamlessly without visible duplication
• Dynamic animation duration — speed scales proportionally to content width for consistent
  scroll velocity across all screen sizes
• Added will-change: transform for smoother GPU-accelerated animation
• Memoized unique testimonials and scroll array with useMemo to avoid unnecessary re-computation

Files Changed

• src/Pages/Home/Testimonial.jsx

Related Issue

Closes #938

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

Please mention these details about yourself here.

1. Contributor Name : Pratik Kumbhar
2. Contributor Email ID : kumbharpratik1213@gmail.com
3. Contributor Github Link : https://github.com/Pratik-1213

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