chore: init embedded DNS server

internal/machine/dns/server.go

@@ -0,0 +1,15 @@
+package dns
+
+import (
+	"context"
+	"net/netip"
+)
+
+// Server provides a DNS server for service discovery and proxying to upstream DNS servers.
+type Server struct {
+	store RecordsStore
+}
+
+type RecordsStore interface {
+	Resolve(ctx context.Context, name string) ([]netip.Addr, error)
+}