Update product detail rarity, heading, and currency

[kylexrich]

Summary

• show the Hercules Beetle rarity as COMMON
• shorten SPECIMEN DETAILS to DETAILS
• append USD to the footer price

Testing

• npx tsc --noEmit --skipLibCheck --jsx react-jsx --esModuleInterop --moduleResolution bundler --module preserve --target esnext app/product/'[id].tsx' constants/products.ts
• npx expo export --platform ios --output-dir /tmp/bug-bazaar-export
• Started the requested iPhone 17 Pro Max / iOS 26.5 session; updated on-device rendering could not be completed because the Revyl remote builder returned build capacity unavailable: no_active_runner on both the initial build and retry.
• The repository-wide npx tsc --noEmit remains blocked by pre-existing errors under demo/versions.

Revyl resources

• Device session
• Referenced App Atlas screen: product_detail
• Reference observation: 9d94ed6e-09c5-4e22-91f2-6b40de6d13bd