ems-core v1.0.0: Standard EMS platform core

Shared backend + frontend for multi-customer EMS deployments.
- 12 enterprise modules: quota, cost, charging, maintenance, analysis, etc.
- 120+ API endpoints, 37 database tables
- Customer config mechanism (CUSTOMER env var + YAML config)
- Collectors: Modbus TCP, MQTT, HTTP API, Sungrow iSolarCloud
- Frontend: React 19 + Ant Design + ECharts + Three.js
- Infrastructure: Redis cache, rate limiting, aggregation engine

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/Dockerfile.prod

@@ -0,0 +1,20 @@
+# Multi-stage production build for standalone use
+# In docker-compose.prod.yml, the nginx Dockerfile handles frontend building directly
+
+# Stage 1: Build
+FROM node:20-alpine AS builder
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+# Stage 2: Serve with nginx
+FROM nginx:1.27-alpine
+COPY --from=builder /app/dist /usr/share/nginx/html
+
+# SPA fallback
+RUN echo 'server { listen 80; root /usr/share/nginx/html; index index.html; location / { try_files $uri $uri/ /index.html; } }' > /etc/nginx/conf.d/default.conf
+
+EXPOSE 80
+CMD ["nginx", "-g", "daemon off;"]