Every package init in the SDK resolves its submodules on attribute
access except four docstring-only leaves - mcp.os.posix, mcp.os.win32,
mcp.server.auth.handlers and mcp.server.auth.middleware - so a chain like
`import mcp; mcp.server.auth.handlers.token` stopped resolving even though
`mcp.client.stdio` and friends do. Give them the same lazy fallback, so
"attribute chains still resolve" is true without a footnote (explicit
imports remain the supported form), and pin one chain through each in the
ratchet.
Max Isbey
cb7c68cf84