feat: add remote worker system for distributed translation

- Add remote translator worker (Docker) that connects via WebSocket
- Add backend Go handlers for remote worker CRUD (REST + WebSocket)
- Add frontend Admin panel for managing remote workers
- Add ProtectedRoute component to secure admin routes
- Add PostgreSQL schema for remote_workers table
- Fix duplicate Load function in config.go
- Fix frontend duplicate fetchStatus function
- Fix Dockerfiles missing go.sum (use go mod download + tidy)

Features:
- Workers connect to server via WebSocket (no ports needed)
- API key authentication per worker
- Job assigner automatically distributes translation jobs
- Worker status tracking (online/offline/disabled)
- Timeout handling for stuck jobs

docker-compose.yml

@@ -312,6 +312,38 @@ services:
         condition: service_healthy
     restart: unless-stopped
 
+  # ==================================================================================
+  # REMOTE TRANSLATOR WORKER - Worker remoto que se conecta por WebSocket
+  # ==================================================================================
+  remote-translator:
+    build:
+      context: .
+      dockerfile: Dockerfile.remote-worker
+    container_name: rss2_remote_translator
+    environment:
+      WORKER_NAME: ${WORKER_NAME:-remote-worker-1}
+      WORKER_API_KEY: ${WORKER_API_KEY:-}
+      WORKER_SERVER: ${WORKER_SERVER:-ws://backend-go:8080/ws/worker}
+      CT2_DEVICE: ${CT2_DEVICE:-cpu}
+      CT2_MODEL_PATH: /app/models/nllb-ct2
+      CT2_COMPUTE_TYPE: ${CT2_COMPUTE_TYPE:-int8}
+      UNIVERSAL_MODEL: facebook/nllb-200-distilled-600M
+      HF_HOME: /app/hf_cache
+      TZ: Europe/Madrid
+    volumes:
+      - ./hf_cache:/app/hf_cache
+      - ./models:/app/models
+    networks:
+      - backend
+    profiles:
+      - remote
+    deploy:
+      resources:
+        limits:
+          cpus: '1'
+          memory: 2G
+    restart: unless-stopped
+
   # ==================================================================================
   # TRANSLATION SCHEDULER - Creates translation jobs
   # ==================================================================================