Specialized Rust compilation profiles

[arthurpaulino]

We want to have two main compilation profiles for the ix Rust crate:

• A profile intended for CI runs
• A profile intended for release builds

Due to the compute-intense characteristics of some of our tests (from Aiur), the profile for CI can be more optimized for execution than the typical debug profile. Doing opt-level = 3 is probably enough.

For maximally optimized release builds, this is what an AI system suggested to me:

[profile.release]
opt-level = 3       # Maximum optimization (for runtime speed)
lto = "fat"         # Full link-time optimization (best perf, slowest compile)
codegen-units = 1   # Forces single-codegen for better cross-function optimization
strip = true        # Removes debug symbols to reduce binary size
panic = "abort"     # Slightly smaller/faster code (optional)

Some of those might be overkill. When we have the Rust pipeline fully integrated (Lean->Ixon compilation + Aiur proving), then we'll be able to better evaluate this multi-dimensional metric and pick the config options that make sense for us.