Add Nashorn Hello World project

- Gradle 9.5.1 (Groovy DSL) build with java + application plugins
- Nashorn standalone engine (org.openjdk.nashorn:nashorn-core:15.6)
- HelloNashorn.java: runs JS via NashornScriptEngineFactory

build.gradle

@@ -0,0 +1,16 @@
+plugins {
+    id 'java'
+    id 'application'
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation 'org.openjdk.nashorn:nashorn-core:15.6'
+}
+
+application {
+    mainClass = 'com.example.HelloNashorn'
+}