feat(mobile): match 100% web functionality and aesthetic for DripZone native Kotlin app
- Integrated requested splash screen dripzone_splash_clean_1787718656035 with SplashActivity
- Aligned dark streetwear palette: #0A0A0A, purple #9333EA, fuchsia #D946EF, glow borders
- Added CitySelectorBottomSheet with Colombian cities, delivery times, and 1st free exchange guarantee
- Implemented multi-product CartManager, CartBottomSheet, breakdown and WhatsApp checkout
- Updated ProductDetailBottomSheet with size chips, Add to Cart, and direct WhatsApp buy
- Added MobileBottomDock with 5 tabs and real-time cart badge counter
- Hardened security: network security config (cleartext blocked), encrypted preferences, tapjacking protection