fix: harden scan edge cases

plugins/services/rabbitmq_test.go

@@ -0,0 +1,20 @@
+package services
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestRabbitMQManagementRejectsGenericHTTP(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		_, _ = w.Write([]byte("plain http service"))
+	}))
+	defer server.Close()
+
+	result := NewRabbitMQPlugin().testManagementInterface(context.Background(), hostInfoFromServer(t, server), testSession())
+	if result.Success {
+		t.Fatalf("testManagementInterface reported generic HTTP as RabbitMQ: %#v", result)
+	}
+}