Add testimonials / user quotes section

[AmitoVrito]

Description

Add a testimonials section on the landing page.

What to do

• Create <Testimonials /> React component
• Show 3-6 quotes with name, role, avatar
• Carousel or grid layout
• Add to src/pages/index.tsx

[AmitoVrito]

Thanks for your interest! I will assign it to you. Before you start, could you give the repo a ⭐ on the main repo (https://github.com/SynapseKit/SynapseKit)? It really helps with visibility for a new project. Looking forward to your PR!