[UX] Add social proof section — testimonials and press mentions

[KunanonJ]

Problem

The page claims '6M+ shoppers' but provides no supporting evidence (no user reviews, no press logos, no star ratings). For a cashback app, trust signals are critical for conversion.

Suggested additions

• User testimonials (3–5 quotes with avatar, name, country)
• Press / media logos if GoGoCash has been featured
• App store rating badge (if native app exists)
• Trust stats bar: '6M+ shoppers · 123 brands · ฿XXM cashback paid out'

Acceptance criteria

• At least 3 real user testimonials with localised names
• Stats are accurate and sourced
• Section renders well on mobile

[KunanonJ]

Still open after code review. components/landing/testimonials-section.tsx exists, but it is not rendered, and the issue requires real testimonials plus sourced stats. Need actual quotes, names/countries or anonymization rules, press logos, or sourced trust stats before this can be safely shipped.