The sink-only change made InitLoggerOptions a union. A caller deriving its
own type from it with Pick (openai-auth: Pick<InitLoggerOptions, 'file' |
'level'>) then got an optional file that fits neither branch, and openai-auth
stopped compiling against 0.8.0. InitLoggerOptions is the file shape again,
exactly as in 0.7.0; SinkOnlyLoggerOptions is its own interface, and the
functions that configure a logger take LoggerOptions, the union of the two.
A type test pins that a picked type keeps file required; making file optional
fails typecheck there.