Summary

Add no_std support to the groupmap crate in proof-systems to enable no-std kimchi verifier.

Context

We are working on making the kimchi verifier no_std compatible for embedded and WASM use cases. This requires all dependency crates to support no_std.

Dependency tier: Leaf crate (no internal dependencies)

Requirements

• Add #![no_std] attribute with conditional std feature
• Add std and alloc features to Cargo.toml
• Replace any std:: imports with core:: or alloc:: equivalents
• Ensure all external dependencies support no_std or are feature-gated

Tracking

Part of the no-std kimchi initiative. See: o1-labs/proof-systems#3413