DEX Method-Count Bin Packer: Multidex SDK Integration

Android caps every DEX file at 65,536 referenced methods, and stacking third-party SDKs onto a mobile app is the single most common way projects hit that ceiling. This simulator models the real build-time decision: toggle a shelf of common SDKs (Firebase, Maps, Facebook, Stripe, push, networking, image loading, video), watch a bin-packing algorithm split their methods across 3D "DEX towers", and compare naive packing order against First-Fit Decreasing. A shrink slider models R8/ProGuard tree-shaking, a multidex switch shows what happens when the build isn't allowed to split at all, and live readouts track total methods, DEX-file count, last-DEX fill percentage, and an illustrative cold-start latency cost.