chore: initial scaffold (Whitelabel-Fork von Pfandsystem)

- Source-Copy von /root/entwicklung/pfandsystem
- docker-compose.yml umgeschrieben: pfandsystem-demo-* Container, Ports 3308/8083/3003 (alle localhost)
- Traefik-Label fuer pfandsystem.dockly.de
- Erweitertes Multi-Tenant-Schema (tenants, tenant_id auf allen Tabellen)
- Neue Tabellen: kunden_bilder, geraete
- Neue Spalten: kunden.anlieferungshinweis, kunden.lieferzeit_bis
- Rollen: superadmin, admin, user, fahrer
- .env.example + README

Code-Refactor (Tailwind, Multi-Tenant-Middleware, Erweiterungen) folgt.

docker-compose.yml

@@ -0,0 +1,98 @@
+version: '3.8'
+
+services:
+  mysql:
+    image: mysql:8.0
+    container_name: pfandsystem-demo-mysql
+    restart: unless-stopped
+    environment:
+      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
+      MYSQL_DATABASE: pfandsystem_demo
+      MYSQL_USER: pfandsystem
+      MYSQL_PASSWORD: ${MYSQL_PASSWORD}
+    volumes:
+      - mysql_data:/var/lib/mysql
+      - ./database/schema.sql:/docker-entrypoint-initdb.d/01-schema.sql:ro
+    ports:
+      - "127.0.0.1:3308:3306"
+    networks:
+      - pfandsystem-demo-net
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "localhost"]
+      timeout: 20s
+      retries: 10
+
+  phpmyadmin:
+    image: phpmyadmin:latest
+    container_name: pfandsystem-demo-phpmyadmin
+    restart: unless-stopped
+    environment:
+      PMA_HOST: mysql
+      PMA_PORT: 3306
+      PMA_USER: pfandsystem
+      PMA_PASSWORD: ${MYSQL_PASSWORD}
+      UPLOAD_LIMIT: 100M
+    ports:
+      - "127.0.0.1:8083:80"
+    networks:
+      - pfandsystem-demo-net
+    depends_on:
+      mysql:
+        condition: service_healthy
+
+  backend:
+    build:
+      context: ./backend
+      dockerfile: Dockerfile
+    container_name: pfandsystem-demo-backend
+    restart: unless-stopped
+    environment:
+      DB_HOST: mysql
+      DB_PORT: 3306
+      DB_USER: pfandsystem
+      DB_PASSWORD: ${MYSQL_PASSWORD}
+      DB_NAME: pfandsystem_demo
+      JWT_SECRET: ${JWT_SECRET}
+      PORT: 3001
+      NODE_ENV: production
+      RESEND_API_KEY: ${RESEND_API_KEY}
+      UPLOAD_DIR: /app/uploads
+      MAX_FILE_SIZE: 10485760
+      SUPERADMIN_EMAIL: ${SUPERADMIN_EMAIL}
+      SUPERADMIN_PASSWORD: ${SUPERADMIN_PASSWORD}
+    volumes:
+      - backend_uploads:/app/uploads
+    ports:
+      - "127.0.0.1:3003:3001"
+    networks:
+      - pfandsystem-demo-net
+    depends_on:
+      mysql:
+        condition: service_healthy
+
+  frontend:
+    image: nginx:1.25-alpine
+    container_name: pfandsystem-demo-frontend
+    restart: unless-stopped
+    volumes:
+      - ./dist:/usr/share/nginx/html:ro
+    networks:
+      - pfandsystem-demo-net
+    labels:
+      - "traefik.enable=true"
+      - "traefik.docker.network=pfandsystem-demo_pfandsystem-demo-net"
+      - "traefik.http.routers.pfandsystem-demo.rule=Host(`pfandsystem.dockly.de`)"
+      - "traefik.http.routers.pfandsystem-demo.entrypoints=web,websecure"
+      - "traefik.http.routers.pfandsystem-demo.tls=true"
+      - "traefik.http.routers.pfandsystem-demo.tls.certresolver=letsencrypt"
+      - "traefik.http.services.pfandsystem-demo.loadbalancer.server.port=80"
+
+volumes:
+  mysql_data:
+    driver: local
+  backend_uploads:
+    driver: local
+
+networks:
+  pfandsystem-demo-net:
+    driver: bridge