CLI: the `otel` config key is ignored, and several help texts are wrong

[hmzakhalid]

Summary

CLI configuration and help-text issues, checked with the 0.18.0 binary.

1. otel in the config file has no effect. With otel: "http://from-yaml:4317" at the top level, interfold config get otel prints an empty value. E3_OTEL=… also prints an empty value. Only --otel works. load_config merges CliOverrides { otel: None, … } last (crates/config/src/app_config.rs:545-553), and None replaces the YAML value.
2. password set help. interfold password --help says Set (or overwrite) a password, but the command refuses when a key file exists.
3. Error text. The refusal says Keyfile already exists. Try using \interfold password set` to set a new password …`, which is the command that failed.
4. nodes restart help. It says Stop the individual node in the nodes set, the same text as nodes stop.
5. noir help. noir status and noir setup have no description.