[$] Safe self-referential data structures in kernel Rust

Self-referential structures that can be used without unsafe codehave posed a problem for Rust for years.There are many cases where a self-referential data structure is the elegantalgorithmic choice, but implementing it in accordance with Rust's lifetime rulesis all but impossible. At Kangrejos 2026, Gary Guo presented a clever solutionto the problem in the context of the kernel'spin_init crate, which helps with the creation of immovable data structures,typically for interoperability with C. Guo's changes could help remove most ofthe unsafe code related to lifetimes in theNova driver and, eventually, other Rust components.