Build MCP SDK Server

Build MCP servers with the official TypeScript SDK v2 on the current main branch. This skill targets @modelcontextprotocol/server; if your code still imports @modelcontextprotocol/sdk, read references/migration-v1-to-v2.md first.

Treat the v2 guidance here as current-sdk guidance, not a production-stability claim. The upstream TypeScript SDK README currently marks v2 as pre-alpha on main, with v1.x still recommended for production until the stable v2 release ships.