deploy(core): add docker files

Dockerfile

@@ -0,0 +1,28 @@
+# ---------- BUILD STAGE ----------
+FROM node:20-alpine AS builder
+
+WORKDIR /app
+
+COPY package.json package-lock.json* ./
+RUN npm install
+
+COPY . .
+
+RUN npm run build
+
+
+# ---------- RUN STAGE ----------
+FROM node:20-alpine AS runner
+
+WORKDIR /app
+
+ENV NODE_ENV=production
+
+# nur notwendige files kopieren (viel kleiner!)
+COPY --from=builder /app/.next/standalone ./
+COPY --from=builder /app/.next/static ./.next/static
+COPY --from=builder /app/public ./public
+
+EXPOSE 3000
+
+CMD ["node", "server.js"]