Add full-stack Hello World app with CI/CD

- Go backend with PostgreSQL connection
- Next.js frontend with TypeScript
- Docker Compose for local development
- Woodpecker CI pipeline for build and push
- Kubernetes manifests with Kustomize
- ArgoCD application for GitOps deployment

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

manifests/frontend-service.yaml

@@ -0,0 +1,16 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: frontend
+  namespace: hell-world
+  labels:
+    app: frontend
+spec:
+  type: ClusterIP
+  ports:
+    - port: 3000
+      targetPort: 3000
+      protocol: TCP
+      name: http
+  selector:
+    app: frontend