Add cron container for daily backups and content export

- Add cron service to docker-compose with backup (3 AM) and export (4 AM) schedules
- Remove redundant content/articles/ and content/curriculum/ (now in Outline, exported to content/wiki/)
- Fix env var mismatch: support both OUTLINE_API_KEY and OUTLINE_API_TOKEN
- Drop updatedAt from export frontmatter to reduce noisy commits
- Add backups/ to gitignore

docker-compose.yml

@@ -68,6 +68,24 @@ services:
       timeout: 5s
       retries: 5
 
+  cron:
+    build:
+      context: .
+      dockerfile: cron/Dockerfile
+    container_name: outline-cron
+    restart: unless-stopped
+    depends_on:
+      - postgres
+    volumes:
+      - ./scripts:/app/scripts:ro
+      - ./content:/app/content
+      - ./.git:/app/.git
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - ~/.ssh:/root/.ssh:ro
+      - ./backups:/backups/outline
+    env_file:
+      - .env
+
 networks:
   dokploy-network:
     external: true