Function detect_mcp_command 

pub fn detect_mcp_command(explicit: Option<&Path>) -> McpCommand

Decide how the MCP entry should invoke mushroomdb, from an explicit --command (if any) and the real environment.

explicit is install’s --command flag; enable has no such flag and always passes None, so it re-derives whatever install would choose right now rather than replaying what an earlier install or disable recorded.