fix(ci): add rust program cache in ci

[ColoCarletti]

No description provided.

[github-actions]

Codex Code Review

1. Medium (Bug / CI correctness): stale Rust ELF cache can bypass recompilation
   • Location: .github/workflows/pr_main.yaml:197, .github/workflows/pr_main.yaml:255
   • The cache key only hashes executor/programs/rust/**, the target JSON, and syscalls/**, but compile behavior is also controlled by Makefile (toolchain pin, build flags, sysroot usage).
   • Because compile is skipped on exact cache hit, changes like nightly-... version/flags in Makefile can leave CI running tests against stale ELF artifacts.
   • Fix: include build-logic inputs in the key (at least Makefile; optionally workflow/toolchain config), or always run make compile-programs-rust and rely on cached executor/shared_target for speed.

No direct Rust/VM runtime security vulnerability is introduced by this diff itself.

[gabrielbosio]

I would replace the .github/actions/setup-rust/action.yaml with Makefile to force recompiling Rust programs when the Rust version set in the Makefile changes.