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>

frontend/Dockerfile

@@ -0,0 +1,23 @@
+FROM node:20-alpine AS builder
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm install
+
+COPY . .
+RUN npm run build
+
+FROM node:20-alpine AS runner
+
+WORKDIR /app
+
+ENV NODE_ENV=production
+
+COPY --from=builder /app/public ./public
+COPY --from=builder /app/.next/standalone ./
+COPY --from=builder /app/.next/static ./.next/static
+
+EXPOSE 3000
+
+CMD ["node", "server.js"]