Heap-allocated values in cross-context calls

After https://github.com/0xMiden/compiler/issues/111

We support scalar values (felt, integers) in function signatures in WIT. To support heap-allocated values (words, structs, etc.) in cross-context calls we need to implement lowering/lifting Wasm CM types for the Miden ABI for `call` op (pointers to stack/advice provider, etc. and back).

The issue references implementing lowering/lifting of Wasm CM types for the Miden ABI for the `call` op, specifically for heap-allocated values like words and structs. Start by examining the code around the `call` op and the existing ABI handling for scalar values. Look at the linked issue #111 for context on WIT function signatures. Determine how pointers to stack/advice provider are managed and what changes are needed to support these new types.

Rédigé par le modèle d'indexation à partir du texte de l'issue.