Remove Dify from ru-docker-infra

Снесены все 7 сервисов (api/worker/web/plugin-daemon/sandbox/ssrf-proxy/
weaviate), их тома, базы dify/dify_plugin и DNS-запись dify.mxti.ru.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

domains.yml

@@ -26,11 +26,6 @@ domains:
         server: ru-docker-infra
         purpose: "portainer UI"
 
-      - host: dify
-        type: A
-        server: ru-docker-infra
-        purpose: "dify через traefik"
-
       - host: n8n
         type: A
         server: nl-reverse-proxy