add domain whois/dns support, refactor codebase

utils/health.go

@@ -0,0 +1,22 @@
+package utils
+
+import (
+	"log/slog"
+	"net/http"
+)
+
+// HealthCheck Returns a simple health check handler.
+func HealthCheck() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, err := w.Write([]byte("OK"))
+		if err != nil {
+			slog.Warn("failed to write healthcheck response",
+				"component", "healthcheck",
+				"method", r.Method,
+				"path", r.URL.Path,
+				"error", err,
+			)
+		}
+	})
+}