Proposal: native MCP protocol primitives in the standard library

MCP (Model Context Protocol) is becoming a standard for AI tool integration. Deno could be the most natural platform for building MCP servers by adding native protocol primitives to the standard library. Currently MCP server authors using Deno must either use the npm package @modelcontextprotocol/sdk (Node.js-focused) or implement JSON-RPC manually over std/http. A Deno-native std/mcp module would provide proper TypeScript types for the MCP protocol, handle JSON-RPC over stdin/stdout and HTTP transports, integrate with Deno's permission model, and require zero configuration. MCP servers are often single-file scripts which maps perfectly to Deno's design. Deno's security model (--allow-read, --allow-net) also maps cleanly to MCP's tool permission concept.