Function parse_emails 

pub(crate) fn parse_emails(raw: &str) -> Result<Vec<String>>

Parse the --emails argument into a list of email addresses.

The legacy CLI accepts four shapes, in order of precedence:

1. A JSON array: ["[email protected]", "[email protected]"]
2. A comma-separated list: [email protected],[email protected]
3. A space-separated list: [email protected] [email protected]
4. A single address: [email protected]

Returns an error if the parsed list is empty or any entry fails a basic shape check.