Add stub

Former-commit-id: ece4239aaa

dns/override/dns_override_android.go

@@ -0,0 +1,18 @@
+//go:build android
+
+package olm
+
+import (
+	"github.com/fosrl/olm/dns"
+)
+
+// SetupDNSOverride is a no-op on Android
+// Android handles DNS through the VpnService API at the Java/Kotlin layer
+func SetupDNSOverride(interfaceName string, dnsProxy *dns.DNSProxy) error {
+	return nil
+}
+
+// RestoreDNSOverride is a no-op on Android
+func RestoreDNSOverride() error {
+	return nil
+}

dns/override/dns_override_ios.go

@@ -0,0 +1,17 @@
+//go:build ios
+
+package olm
+
+import (
+	"github.com/fosrl/olm/dns"
+)
+
+// SetupDNSOverride is a no-op on iOS as DNS configuration is handled by the system
+func SetupDNSOverride(interfaceName string, dnsProxy *dns.DNSProxy) error {
+	return nil
+}
+
+// RestoreDNSOverride is a no-op on iOS as DNS configuration is handled by the system
+func RestoreDNSOverride() error {
+	return nil
+}