feat: migrate to standard Docker-based CI/CD deployment

- Add Dockerfile for building Next.js images
- Replace init-container deployment with standard deployment
- Add kustomization with image tag tracking
- Add deploy.sh script for CI/CD pipeline

This enables proper GitOps auto-deployment:
1. Build image with commit hash tag
2. Push to GHCR
3. Update kustomization.yaml image tag
4. Flux detects change and restarts pods

k8s/kustomization.yaml

@@ -1,6 +1,11 @@
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
-  - deployment-nodejs.yaml
+  - deployment.yaml
   - service.yaml
   - ingress.yaml
+
+# Images field allows Flux ImageUpdateAutomation to update the tag
+images:
+  - name: ghcr.io/unchainedio/manoon-headless
+    newTag: 467b513  # This will be updated by CI/CD