chore: initial project setup with backend, frontend, CI/CD, and documentation

Add complete NexaFabric project structure including:
- FastAPI backend with SQLAlchemy models, JWT auth, RBAC, audit logging, and provider interfaces
- React + TypeScript frontend with Vite, Tailwind CSS, TanStack Query, and Zustand
- Docker Compose configuration for PostgreSQL, Redis, API, worker, frontend, and nginx
- GitHub Actions and GitLab CI workflows for testing, linting, building, and security scanning
- Environment

docker-compose.prod.yml

@@ -0,0 +1,64 @@
+services:
+  postgres:
+    image: postgres:16-alpine
+    restart: unless-stopped
+    env_file: .env
+    volumes:
+      - postgres-data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U $$POSTGRES_USER -d $$POSTGRES_DB"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  redis:
+    image: redis:7-alpine
+    restart: unless-stopped
+    command: ["redis-server", "--appendonly", "yes"]
+    volumes:
+      - redis-data:/data
+
+  api:
+    build: ./backend
+    restart: unless-stopped
+    env_file: .env
+    depends_on:
+      postgres:
+        condition: service_healthy
+      redis:
+        condition: service_started
+
+  worker:
+    build: ./backend
+    restart: unless-stopped
+    env_file: .env
+    command: ["python", "-m", "app.workers.worker"]
+    depends_on:
+      - api
+
+  frontend:
+    build: ./frontend
+    restart: unless-stopped
+    depends_on:
+      - api
+
+  proxy:
+    image: caddy:2-alpine
+    restart: unless-stopped
+    ports:
+      - "80:80"
+      - "443:443"
+    volumes:
+      - ./deploy/caddy/Caddyfile:/etc/caddy/Caddyfile:ro
+      - caddy-data:/data
+      - caddy-config:/config
+    depends_on:
+      - frontend
+      - api
+
+volumes:
+  postgres-data:
+  redis-data:
+  caddy-data:
+  caddy-config:
+