isIPv6 static method
Returns true if the host is an IPv6 address.
Implementation
static bool isIPv6(String host) {
// Basic IPv6 validation
if (!host.contains(':')) return false;
if (host.contains(':::')) return false;
final parts = host.split(':');
if (parts.length > 8) return false;
for (final part in parts) {
if (part.isEmpty) continue;
if (int.tryParse(part, radix: 16) == null) return false;
}
return true;
}