Fix testimonial slider clipping and card width inconsistency

[the11dev]

Fixes #573, #632

Problem
The testimonial section has two issues affecting the homepage:

• first card gets clipped at 90–100% zoom and on narrower viewports
• cards resize based on content length, creating inconsistent widths

Before:

Recording.2026-08-05.192104.mp4

After:

Untitled.design.1.mp4

Root Cause
The slider container uses justify-center with overflow-x-scroll, which pushes content past the scroll origin i.e the browser can't scroll back to the first card. Additionally, cards lack fixed widths so they size based on how much text they contain.

Changes
TestimonialSection/index.tsx:

• Removed justify-center from the scroll container (root cause of the clipping)
• Added an inner inline-flex mx-auto wrapper so cards still center when they all fit on screen, but don't clip when they overflow

Testimonial/index.tsx:

• Added fixed widths (w-[300px] / sm:w-[340px]) for consistent card sizing