Draft detailed implementation guidelines for the Rust SDK for Solana AI Registries. Use the reference documentation in docs/sdk_refs/rust_sdk_references.md as the main source for all steps, required features, and testing requirements. Include:

• Atomic implementation tasks
• Feature gates and payment mode flags
• CI/CD publishing workflow notes
• Code style and review requirements
• Reference links to IDLs, constants, and related artifacts

Ensure all guidelines are actionable and reference the relevant files.