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-deployment.yaml

@@ -0,0 +1,45 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: frontend
+  namespace: hell-world
+  labels:
+    app: frontend
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: frontend
+  template:
+    metadata:
+      labels:
+        app: frontend
+    spec:
+      containers:
+        - name: frontend
+          image: registry.gecore.mn/library/hell-world-frontend:latest
+          ports:
+            - containerPort: 3000
+              name: http
+          env:
+            - name: NEXT_PUBLIC_API_URL
+              value: "https://hell-world-api.gecore.mn"
+          resources:
+            requests:
+              memory: "128Mi"
+              cpu: "100m"
+            limits:
+              memory: "256Mi"
+              cpu: "200m"
+          livenessProbe:
+            httpGet:
+              path: /
+              port: 3000
+            initialDelaySeconds: 10
+            periodSeconds: 10
+          readinessProbe:
+            httpGet:
+              path: /
+              port: 3000
+            initialDelaySeconds: 5
+            periodSeconds: 5