write MidenVM constraints for the stack u32 ops

These constraints should be deferred until after we have decided how to deal with the top level stack constraints and op flag handling in #209.

The u32 op constraints are described [here](https://0xpolygonmiden.github.io/miden-vm/design/stack/u32_ops.html) and implemented in Rust [here](https://github.com/0xPolygonMiden/miden-vm/blob/main/air/src/stack/u32_ops/mod.rs).

The issue references existing Rust implementation in the Miden VM repository (air/src/stack/u32_ops/mod.rs) and design documentation. First, understand the deferred constraint handling from issue #209. Then, study the u32 operations specification and the existing Rust code to translate the constraints into Air-Script. The work is blocked on a prior architectural decision.

Scritto dal modello di indicizzazione a partire dal testo della issue.