//! Shared pieces between the two MCP surfaces:
//!
//! - `travelagent-tui::mcp_bridge` (the `--mcp-alongside` in-process bridge),
//! - `travelagent-mcp::server` (the standalone `trv --mcp` binary).
//!
//! Both servers expose an overlapping set of tools and historically defined
//! their own copies of the same request DTOs, the same `since`-cursor filter,
//! and the same ingress body-size guard. This module holds the canonical
//! versions so the two surfaces can't drift.
//!
//! What lives here is *data and stateless helpers only* — request shapes,
//! filter predicates, size-cap checks. Tool dispatch, state ownership, and
//! the async runtime remain with each server.