Add no-std support to poly-commitment crate

[dannywillems]

Summary

Add no_std support to the poly-commitment 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: Core cryptographic layer (depends on o1-utils, mina-poseidon, mina-curves, groupmap)

Known blockers

• rayon usage for parallel MSM - needs feature gate
• rmp-serde for serialization - needs feature gate
• serde_with - check no-std compatibility

Requirements

• Add #![no_std] attribute with conditional std feature
• Add std and alloc features to Cargo.toml
• Feature-gate rayon behind std or parallel feature
• Feature-gate rmp-serde behind std feature
• Replace any std:: imports with core:: or alloc:: equivalents
• Ensure IPA/KZG verification works in no-std mode

Dependencies

Requires these crates to have no-std support first:

• o1-utils
• groupmap
• mina-poseidon (already no-std)
• mina-curves

Tracking

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