cleosrv & cleoc: Support "--config none" to specify running without a config file

> If a flag can accept an optional value, allow a special word like “none.” For example, ssh -F takes an optional filename of an alternative ssh_config file, and ssh -F none runs SSH with no config file. Don’t just use a blank value—this can make it ambiguous whether arguments are flag values or arguments.

https://clig.dev/#arguments-and-flags

Start by locating the cleosrv and cleoc command-line flag definitions and how each reads its config file. The issue points to clig.dev's guidance on optional flag values; check existing tests for config handling and add coverage for the requested `--config none` behavior. Done means both commands can run without a config file when that value is supplied.

Written by the indexing model from the issue text.