- extractCertInfo now returns an error (ErrNoPeerCertificates) instead
of an empty struct when there are no peer certificates
- SubjectAlternativeNames now includes both DNS names and IP addresses
from cert.IPAddresses
Addresses review feedback on PR #7.
Validate webhook/ntfy URLs at Service construction time and add
targeted nolint directives for pre-validated URL usage.
Fix goimports formatting in tlscheck_test.go.