cmd/cli: use powershell to set/reset DNS on Windows

Using netsh command will emit unexpected SOA queries, do not use it.

While at it, also ensure that local ipv6 will be added to nameservers
list on systems that require ipv6 local listener.

cmd/cli/prog.go

@@ -588,6 +588,10 @@ func (p *prog) setDNS() {
 	if needRFC1918Listeners(lc) {
 		nameservers = append(nameservers, ctrld.Rfc1918Addresses()...)
 	}
+	if needLocalIPv6Listener() {
+		nameservers = append(nameservers, "::1")
+	}
+	slices.Sort(nameservers)
 	if err := setDNS(netIface, nameservers); err != nil {
 		logger.Error().Err(err).Msgf("could not set DNS for interface")
 		return
@@ -665,7 +669,7 @@ func (p *prog) dnsWatchdog(iface *net.Interface, nameservers []string, allIfaces
 					}
 				}
 				if allIfaces {
-					withEachPhysicalInterfaces(iface.Name, "re-applying DNS", func(i *net.Interface) error {
+					withEachPhysicalInterfaces(iface.Name, "", func(i *net.Interface) error {
 						if dnsChanged(i, ns) {
 							if err := setDnsIgnoreUnusableInterface(i, nameservers); err != nil {
 								mainLog.Load().Error().Err(err).Str("iface", i.Name).Msgf("could not re-apply DNS settings")
@@ -977,7 +981,11 @@ func savedStaticNameservers(iface *net.Interface) []string {
 func dnsChanged(iface *net.Interface, nameservers []string) bool {
 	curNameservers, _ := currentStaticDNS(iface)
 	slices.Sort(curNameservers)
-	return !slices.Equal(curNameservers, nameservers)
+	if !slices.Equal(curNameservers, nameservers) {
+		mainLog.Load().Debug().Msgf("interface %q current DNS settings: %v, expected: %v", iface.Name, curNameservers, nameservers)
+		return true
+	}
+	return false
 }
 
 // selfUninstallCheck checks if the error dues to controld.InvalidConfigCode, perform self-uninstall then.