//! FDKEY — AI-agent verification SDK for MCP servers.
//!
//! This is a name-reservation placeholder. The real `fdkey` Rust SDK lands
//! shortly — it will provide a `with_fdkey()` middleware that gates any
//! MCP server behind an LLM-only verification challenge, mirroring the
//! TypeScript SDK at <https://www.npmjs.com/package/@fdkey/mcp>.
//!
//! See <https://fdkey.com>.
/// Placeholder marker. Returns a static string pointing at the real release.