mcp: preserve transport errors in Write error chain#888

jpugliesi wants to merge 2 commits intomodelcontextprotocol:mainmodelcontextprotocol/go-sdk:mainfrom

jpugliesi:jpugliesi/wrap-round-tripper-errorjpugliesi/go-sdk:jpugliesi/wrap-round-tripper-errorCopy head branch name to clipboard