Add a new required secret key `SECRET_KEY` referencing `CRAWL4AI_SECRET` in the openwebui-secret configuration, and define the corresponding template entry with generation via `openssl hex 32`. This enables secure authentication for the Crawl4AI integration.
Added new searxng and crawl4ai services with their secrets and environment variables for web search and crawling. Updated existing container names to use `-app` suffix and adjusted references. Added necessary directory creation for new services.
