fix: add lifespan context manager to StreamableHTTP mounting examples#1669

Kludex merged 3 commits intomodelcontextprotocol:mainmodelcontextprotocol/python-sdk:mainfrom

TheMailmans:fix/streamable-http-mounting-lifespanTheMailmans/python-sdk:fix/streamable-http-mounting-lifespanCopy head branch name to clipboard