feat: Initial commit - Train tracking system

Complete real-time train tracking system for Spanish railways (Renfe/Cercanías):

- Backend API (Node.js/Express) with GTFS-RT polling workers
- Frontend dashboard (React/Vite) with Leaflet maps
- Real-time updates via Socket.io WebSocket
- PostgreSQL/PostGIS database with Flyway migrations
- Redis caching layer
- Docker Compose configuration for development and production
- Gitea CI/CD workflows (lint, auto-tag, release)
- Production deployment with nginx + Let's Encrypt SSL

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/Dockerfile

@@ -0,0 +1,69 @@
+# Multi-stage Dockerfile para Frontend React + Vite
+FROM node:20-alpine AS build
+
+# Argumentos de construcción
+ARG VITE_API_URL
+ARG VITE_WS_URL
+
+ENV VITE_API_URL=${VITE_API_URL}
+ENV VITE_WS_URL=${VITE_WS_URL}
+
+WORKDIR /app
+
+# Copiar archivos de dependencias
+COPY package*.json ./
+
+# Instalar dependencias
+RUN npm install
+
+# Copiar código fuente
+COPY . .
+
+# Build de producción
+RUN npm run build
+
+# ================================
+# Stage de producción con Nginx
+# ================================
+FROM nginx:alpine AS production
+
+# Copiar archivos compilados
+COPY --from=build /app/dist /usr/share/nginx/html
+
+# Copiar configuración de nginx personalizada
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+
+# Crear usuario no-root y configurar permisos
+RUN chown -R nginx:nginx /usr/share/nginx/html && \
+    chown -R nginx:nginx /var/cache/nginx && \
+    chown -R nginx:nginx /var/log/nginx && \
+    chown nginx:nginx /etc/nginx/conf.d/default.conf && \
+    chmod 644 /etc/nginx/conf.d/default.conf && \
+    touch /var/run/nginx.pid && \
+    chown -R nginx:nginx /var/run/nginx.pid
+
+USER nginx
+
+EXPOSE 80
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD wget --quiet --tries=1 --spider http://localhost/ || exit 1
+
+CMD ["nginx", "-g", "daemon off;"]
+
+# ================================
+# Stage de desarrollo
+# ================================
+FROM node:20-alpine AS development
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm install
+
+COPY . .
+
+EXPOSE 5173
+
+CMD ["npm", "run", "dev", "--", "--host", "0.0.0.0"]