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

Dockerfile

@@ -0,0 +1,30 @@
+# Multi-stage build for Next.js
+FROM node:20-slim AS builder
+
+WORKDIR /app
+
+# Copy package files
+COPY package*.json ./
+RUN npm ci --prefer-offline --no-audit
+
+# Copy source and build
+COPY . .
+RUN npm run build
+
+# Production stage
+FROM node:20-slim AS runner
+
+WORKDIR /app
+
+ENV NODE_ENV=production
+ENV PORT=3000
+ENV HOSTNAME=0.0.0.0
+
+# Copy necessary files from builder
+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"]