fix npm bug

frontend/Dockerfile

@@ -1,19 +1,26 @@
+# Build context is the repo root (npm workspaces share one root package-lock.json)
 FROM node:22-alpine AS builder
 
 WORKDIR /app
 
 COPY package.json package-lock.json ./
-RUN npm ci
+COPY frontend/package.json frontend/
+COPY admin/package.json admin/
+COPY backend/package.json backend/
+RUN npm ci -w frontend
 
-COPY . .
-RUN npm run build
+ARG VITE_BACKEND_URL
+ENV VITE_BACKEND_URL=$VITE_BACKEND_URL
+
+COPY frontend/ frontend/
+RUN npm run build -w frontend
 
 FROM nginx:alpine AS runner
 
 WORKDIR /usr/share/nginx/html
-COPY --from=builder /app/dist .
+COPY --from=builder /app/frontend/dist .
 
-COPY nginx.conf /etc/nginx/conf.d/default.conf
+COPY frontend/nginx.conf /etc/nginx/conf.d/default.conf
 
 EXPOSE 80
-CMD ["nginx", "-g", "daemon off;"]
+CMD ["nginx", "-g", "daemon off;"]