Implement a skip list in Rust in this directory as a small library crate: Cargo.toml, src/lib.rs (a generic SkipList<K: Ord, V> with insert, get, remove, len, and an ordered iterator; probabilistic levels with a seeded RNG so tests are deterministic), src/lru.rs (an LruCache<K, V> with O(1) get/put built on HashMap + a doubly-linked list of indices), and tests in each file's #[cfg(test)] module including a property test comparing SkipList against std::collections::BTreeMap over 10_000 random ops. Run cargo test and fix failures until everything passes.