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/ingress.yaml

@@ -0,0 +1,38 @@
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: hell-world
+  namespace: hell-world
+  annotations:
+    cert-manager.io/cluster-issuer: letsencrypt-prod
+    nginx.ingress.kubernetes.io/ssl-redirect: "true"
+spec:
+  ingressClassName: nginx
+  tls:
+    - hosts:
+        - hell-world.gecore.mn
+        - hell-world-api.gecore.mn
+      secretName: hell-world-tls
+  rules:
+    # Frontend
+    - host: hell-world.gecore.mn
+      http:
+        paths:
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: frontend
+                port:
+                  number: 3000
+    # Backend API
+    - host: hell-world-api.gecore.mn
+      http:
+        paths:
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: backend
+                port:
+                  number: 8080