chore: add package.json with dependencies and test scripts

package.json

@@ -0,0 +1,24 @@
+{
+  "name": "hello-world-app",
+  "version": "1.0.0",
+  "description": "Simple web app for CI/CD demo",
+  "main": "src/server.js",
+  "scripts": {
+    "start": "node src/server.js",
+    "test": "jest",
+    "test:unit": "jest --testPathPattern=tests/unit",
+    "test:integration": "jest --testPathPattern=tests/integration",
+    "test:e2e": "jest --testPathPattern=tests/e2e"
+  },
+  "dependencies": {
+    "express": "^4.18.2"
+  },
+  "devDependencies": {
+    "axios": "^1.4.0",
+    "jest": "^29.6.2",
+    "supertest": "^6.3.3"
+  },
+  "jest": {
+    "testEnvironment": "node"
+  }
+}