MCP Code Mode: search_tools and execute_typescript

By default the MCP server now lists two tools instead of one per operation. search_tools returns typed TypeScript declarations for the tools a connection can reach, and execute_typescript runs a short program that calls them in a sandbox, so an agent can batch several calls into one round trip.

Every call inside a program goes through the same scope checks, metering and audit as a direct tool call. A refused call throws an error inside the program carrying a stable code.