Add Dockerfile for multi-stage build (node → nginx)

Dockerfile

@@ -0,0 +1,17 @@
+# Stage 1: Build
+FROM node:20-alpine AS build
+WORKDIR /app
+COPY package.json bun.lock ./
+RUN npm install
+COPY . .
+ARG VITE_API_URL=https://api.nkode.donovankelly.xyz
+ENV VITE_API_URL=$VITE_API_URL
+RUN npm run build
+
+# Stage 2: Serve
+FROM nginx:alpine
+COPY --from=build /app/dist /usr/share/nginx/html
+# SPA routing: all paths → index.html
+RUN printf 'server {\n  listen 80;\n  root /usr/share/nginx/html;\n  index index.html;\n  location / {\n    try_files $uri $uri/ /index.html;\n  }\n}\n' > /etc/nginx/conf.d/default.conf
+EXPOSE 80
+CMD ["nginx", "-g", "daemon off;"]