Simplify Docker deployment

Dockerfile

@@ -1,7 +1,28 @@
-FROM dhi.io/node:23-alpine3.21-dev
-WORKDIR /usr/src/app
-COPY package*.json ./
-RUN npm install
+FROM node:22-alpine AS builder
+
+WORKDIR /app
+
+# Install dependencies first (better layer caching)
+COPY package.json package-lock.json ./
+RUN npm ci
+
+# Copy source and build
 COPY . .
-CMD ["npm", "run", "build"]
-CMD ["node", "-r", "dotenv/config", "build"]
+RUN npm run build
+
+# Production image
+FROM node:22-alpine
+
+WORKDIR /app
+
+# Only copy what we need for production
+COPY --from=builder /app/build ./build
+COPY --from=builder /app/package.json ./
+COPY --from=builder /app/package-lock.json ./
+
+# Install production dependencies only (including dotenv)
+RUN npm ci --omit=dev
+
+EXPOSE 3001
+
+CMD ["node", "-r", "dotenv/config", "build"]