Valen Language Enables Safe Mutable Rust References

Valen, an experimental successor to Vale, now implements group borrowing, allowing multiple mutable references to the same object, including Rust objects, without Rust's shared-xor-mutable restriction. This upholds memory safety across the Valen/Rust boundary via invalidation tracking, letting Valen call Rust functions seamlessly and potentially simplify code that Rust's borrow checker rejects.