feat: add Docker deployment configuration

Add backend and frontend Dockerfiles, docker-compose setup with nginx
reverse proxy, .dockerignore files and Makefile for dev/prod workflows.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/Dockerfile

@@ -0,0 +1,12 @@
+FROM node:22-alpine AS build
+
+WORKDIR /app
+COPY package.json package-lock.json* ./
+RUN npm install
+COPY . .
+RUN npm run build
+
+FROM nginx:alpine
+COPY --from=build /app/dist /usr/share/nginx/html
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+EXPOSE 80