feat: production deployment - full update with providers, admin, glossaries, pricing, tests

Major changes across backend, frontend, infrastructure:
- Provider system with model selection (Google, DeepL, OpenAI, Ollama, Google Cloud)
- Admin panel: user management, pricing, settings
- Glossary system with CSV import/export
- Subscription and tier quota management
- Security hardening (rate limiting, API key auth, path traversal fixes)
- Docker compose for dev, prod, and IONOS deployment
- Alembic migrations for new tables
- Frontend: dashboard, pricing page, landing page, i18n (en/fr)
- Test suite and verification scripts

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

docker-compose.dev.yml

@@ -1,40 +1,140 @@
 # Document Translation API - Development Docker Compose
-# Usage: docker-compose -f docker-compose.yml -f docker-compose.dev.yml up
+# Usage: docker compose -f docker-compose.dev.yml up
+#        (or: docker-compose -f docker-compose.dev.yml up)
+#
+# Starts: backend (FastAPI :8000), frontend (Next.js :3000), PostgreSQL, Redis
+# Hot reload: backend and frontend code mounted as volumes
+# Environment: loaded from .env at project root (env_file and Compose substitution)
 
 version: '3.8'
 
 services:
+  # ===========================================
+  # PostgreSQL Database
+  # ===========================================
+  postgres:
+    image: postgres:16-alpine
+    container_name: translate-postgres-dev
+    environment:
+      - POSTGRES_USER=${POSTGRES_USER:-translate}
+      - POSTGRES_PASSWORD=${POSTGRES_PASSWORD:-translate_secret_123}
+      - POSTGRES_DB=${POSTGRES_DB:-translate_db}
+      - PGDATA=/var/lib/postgresql/data/pgdata
+    volumes:
+      - postgres_data_dev:/var/lib/postgresql/data
+    networks:
+      - translate-network
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER:-translate} -d ${POSTGRES_DB:-translate_db}"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+      start_period: 10s
+
+  # ===========================================
+  # Redis
+  # ===========================================
+  redis:
+    image: redis:7-alpine
+    container_name: translate-redis-dev
+    command: redis-server --appendonly yes --maxmemory 256mb --maxmemory-policy allkeys-lru
+    volumes:
+      - redis_data_dev:/data
+    networks:
+      - translate-network
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+      start_period: 5s
+
+  # ===========================================
+  # Backend API (FastAPI) - hot reload
+  # ===========================================
   backend:
     build:
       context: .
       dockerfile: docker/backend/Dockerfile
-      target: builder  # Use builder stage for dev
-    volumes:
-      - .:/app
-      - /app/venv  # Don't override venv
+      target: builder
+    container_name: translate-backend-dev
+    env_file:
+      - .env
     environment:
       - DEBUG=true
       - LOG_LEVEL=DEBUG
+      - DATABASE_URL=postgresql+asyncpg://${POSTGRES_USER:-translate}:${POSTGRES_PASSWORD:-translate_secret_123}@postgres:5432/${POSTGRES_DB:-translate_db}
+      - REDIS_URL=redis://redis:6379/0
+    volumes:
+      - .:/app
+      - backend_venv:/opt/venv
     command: uvicorn main:app --host 0.0.0.0 --port 8000 --reload
     ports:
       - "8000:8000"
+    networks:
+      - translate-network
+    depends_on:
+      postgres:
+        condition: service_healthy
+      redis:
+        condition: service_healthy
+    healthcheck:
+      test: ["CMD-SHELL", "python -c \"import urllib.request; urllib.request.urlopen('http://localhost:8000/health')\" || exit 1"]
+      interval: 10s
+      timeout: 5s
+      retries: 3
+      start_period: 15s
 
+  # ===========================================
+  # Frontend (Next.js) - hot reload
+  # ===========================================
   frontend:
     build:
       context: .
       dockerfile: docker/frontend/Dockerfile
       target: builder
-    volumes:
-      - ./frontend:/app
-      - /app/node_modules
-      - /app/.next
+      args:
+        - NEXT_PUBLIC_API_URL=${NEXT_PUBLIC_API_URL:-http://localhost:8000}
+    container_name: translate-frontend-dev
+    env_file:
+      - .env
     environment:
       - NODE_ENV=development
+      # Proxy Next : navigateur → /api/* → backend (évite CORS et l’hostname `backend` côté client)
+      - BACKEND_URL=http://backend:8000
+      # Vide = URLs relatives + proxy. Sinon URL joignable depuis le navigateur (ex. http://localhost:8000)
+      - NEXT_PUBLIC_API_URL=${NEXT_PUBLIC_API_URL:-}
+    volumes:
+      - ./frontend:/app
+      - frontend_node_modules:/app/node_modules
+      - frontend_next:/app/.next
     command: npm run dev
     ports:
       - "3000:3000"
+    networks:
+      - translate-network
+    depends_on:
+      backend:
+        condition: service_healthy
 
-  # No nginx in dev - direct access to services
-  nginx:
-    profiles:
-      - disabled
+# ===========================================
+# Networks
+# ===========================================
+networks:
+  translate-network:
+    driver: bridge
+
+# ===========================================
+# Volumes (dev-only names to avoid clashing with prod)
+# ===========================================
+volumes:
+  postgres_data_dev:
+    driver: local
+  redis_data_dev:
+    driver: local
+  backend_venv:
+    driver: local
+  frontend_node_modules:
+    driver: local
+  frontend_next:
+    driver: local