Copilot review: the option's doc still promised the level is set "if server
supports logging" — after the era gate that is exactly the case which now
silently does nothing, since a modern server can advertise `logging` and still
ignore the option.
Document it as legacy-only and point modern callers at the per-request
`io.modelcontextprotocol/logLevel` opt-in (`modernLogLevel` /
`setModernLogLevel()`).
Signed-off-by: cliffhall <cliff@futurescale.com>
e746665eb6