Introduce a dedicated --logs mode for CLI log viewing with --tail <lines> and
-f/--follow streaming from the normal/debug log channel, keep user-facing CLI
output free of timestamped log formatting, and update bash/zsh completions for
the new logs flags.
Add a System setting for Off/Normal/Debug logging, apply readable local timestamps to backend logs, and enable exporting buffered runtime logs to a file when debug mode is active.
Co-authored-by: Maxim Isaev <im@friclub.ru>