Add frontend deploy command and fix toggle/flickering

- Add 'deploy' command to frontend/start.sh that builds and copies
  to nginx root (/var/www/mybeacon/frontend)
- Use unique .slider-large class to avoid Vue scoped CSS conflicts
- Show loading only when no devices (prevent table flickering)
- Update DEV_CONTAINER_README with deployment info

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

DEV_CONTAINER_README.md

@@ -138,13 +138,19 @@ cd frontend
 npm install
 
 # Run dev server (with HMR)
-npm run dev -- --host 0.0.0.0
+./start.sh dev
 
-# Build for production
-npm run build
+# Build and deploy to nginx (RECOMMENDED)
+./start.sh deploy
 
-# Preview production build
-npm run preview
+# Build only (without deploy)
+./start.sh build
+```
+
+**IMPORTANT:** Frontend is served by nginx from `/var/www/mybeacon/frontend`.
+After building, you MUST deploy to nginx:
+```bash
+./start.sh deploy   # Build + copy to nginx
 ```
 
 ## API Endpoints

frontend/start.sh

@@ -68,6 +68,26 @@ case "$MODE" in
         echo ""
         npm run build
         echo -e "${GREEN}Build complete!${NC}"
+        echo -e "${YELLOW}Run '$0 deploy' to copy to nginx${NC}"
+        ;;
+
+    deploy)
+        echo -e "${GREEN}Building and deploying to nginx...${NC}"
+        echo ""
+
+        # Build
+        npm run build
+
+        # Copy to nginx root
+        NGINX_ROOT="/var/www/mybeacon/frontend"
+        echo -e "${YELLOW}Copying to ${NGINX_ROOT}...${NC}"
+
+        sudo rm -rf "${NGINX_ROOT}"/*
+        sudo cp -r dist/* "${NGINX_ROOT}/"
+        sudo chown -R www-data:www-data "${NGINX_ROOT}"
+
+        echo -e "${GREEN}Deploy complete!${NC}"
+        echo -e "Frontend: ${YELLOW}http://localhost:80${NC}"
         ;;
 
     preview)
@@ -138,11 +158,12 @@ case "$MODE" in
         ;;
 
     *)
-        echo "Usage: $0 {dev|build|preview|background|stop|restart|status|clean|install}"
+        echo "Usage: $0 {dev|build|deploy|preview|background|stop|restart|status|clean|install}"
         echo ""
         echo "Modes:"
         echo "  dev        - Development server with HMR"
-        echo "  build      - Build for production"
+        echo "  build      - Build for production (output: ./dist/)"
+        echo "  deploy     - Build and copy to nginx (/var/www/mybeacon/frontend)"
         echo "  preview    - Preview production build"
         echo "  background - Run dev server in background"
         echo "  stop       - Stop frontend"
@@ -157,8 +178,8 @@ case "$MODE" in
         echo ""
         echo "Examples:"
         echo "  $0 dev                    # Development mode"
-        echo "  $0 background             # Background mode"
-        echo "  $0 build                  # Build production"
+        echo "  $0 deploy                 # Build + deploy to nginx"
+        echo "  $0 build                  # Build only (no deploy)"
         echo "  PORT=3000 $0 dev          # Custom port"
         exit 1
         ;;