feat: add Dockerfile for Dokploy deployment

Dockerfile

@@ -0,0 +1,26 @@
+FROM node:20-alpine AS builder
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm ci
+
+COPY . .
+RUN npm run build
+
+# ── Runtime ──────────────────────────────────────────
+FROM node:20-alpine AS runtime
+
+WORKDIR /app
+
+COPY --from=builder /app/dist ./dist
+COPY --from=builder /app/node_modules ./node_modules
+COPY --from=builder /app/package.json ./package.json
+
+ENV HOST=0.0.0.0
+ENV PORT=4321
+ENV NODE_ENV=production
+
+EXPOSE 4321
+
+CMD ["node", "./dist/server/entry.mjs"]