Dockerfile

# ---------- build stage ----------
FROM node:20-slim AS builder
WORKDIR /app

# Install deps (non-strict to avoid lockfile mismatches)
COPY frontend/package*.json frontend/
COPY backend/package*.json backend/
RUN npm install --prefix frontend
RUN npm install --omit=dev --prefix backend

# Copy sources
COPY frontend ./frontend
COPY backend ./backend

# Build React app
RUN npm run build --prefix frontend

# ---------- runtime ----------
FROM node:20-slim
WORKDIR /app

# Bring backend + built frontend
COPY --from=builder /app/backend ./backend
COPY --from=builder /app/frontend/dist ./frontend/dist

ENV NODE_ENV=production
# Hugging Face sets $PORT (usually 7860). We bind to it explicitly.
ENV PORT=7860
EXPOSE 7860

# Start Express (serves /api + frontend/dist)
CMD ["node", "backend/src/server.js"]