Memory optimization for feeds on Android

What this post added

Introduced `LongArraySet` and `IntArraySet` data structures to mitigate memory overhead caused by Java autoboxing when storing primitive `long` and `int` values in collections like `HashSet`. These custom structures leverage `LongSparseArray` and `IntSparseArray` respectively, offering a more memory-efficient alternative for scenarios with hundreds of items, thereby reducing garbage collection pauses and improving scrolling performance on Android.