Function normalize_egress_patterns 

pub fn normalize_egress_patterns(
    patterns: &[String],
    label: &str,
) -> Result<Vec<String>>

Validate and canonicalize a whole egress allowlist, sorted and deduplicated.

label names the surface in the error so an operator can find the offending entry (for example plugins.entries[github].egress_hosts).

Errors

Returns an error naming every rejected entry and why.