pub const MCP_USER_PROGRESS_CBS: &str = "__mcp_user_progress_cbs";Expand description
Global table that holds user-provided progress callbacks stored by server name on the main Isle.
Written by mcp.on_progress (main Isle bridge) so that on_progress
notifications dispatched via main_isle.exec can call the closure with its
upvalues intact (no bytecode dump/reload across Lua VMs).