Add production Docker setup and update backend/frontend configs

Introduces .dockerignore, production Dockerfile and nginx config for frontend, and refactors docker-compose.yml for multi-service deployment. Updates backend and frontend code to support public API tagging, improves refund handling, adds test email endpoint, and migrates Orval config to TypeScript. Removes unused frontend Dockerfile and updates dependencies for React Query and Orval.

frontend/Dockerfile.prod

@@ -0,0 +1,16 @@
+# Step 1: Build React (Vite) app
+FROM node:22-alpine AS build
+WORKDIR /app
+COPY package*.json ./
+# If package-lock.json exists, npm ci is faster and reproducible
+RUN npm ci || npm install
+COPY . .
+ENV NODE_ENV=production
+RUN npm run build
+
+# Step 2: Nginx runtime
+FROM nginx:1.27-alpine
+COPY nginx/nginx.conf /etc/nginx/conf.d/default.conf
+COPY --from=build /app/dist /usr/share/nginx/html
+EXPOSE 80
+CMD ["nginx", "-g", "daemon off;"]