Prod: new admin on admin.*, old admin moves to admin.*/old/

Dockerfile builds apps/backoffice into /srv/admin and the old admin with
base /old/; nginx serves /old/ with its own uncached index.html.
Worker notification links point to the new admin pages (moves, requests,
chats); BACKOFFICE_URL defaults to ADMIN_URL.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

infra/prod/Dockerfile

@@ -1,6 +1,7 @@
 # Barev Club — образы для продакшена.
 #   app  — Node: API + воркер + боты (один процесс) и лендинг Next.js (тот же образ)
 #   web  — nginx: статика Mini App и админки + прокси /trpc и /files на API
+#          admin.* — новая админка (apps/backoffice), admin.*/old/ — старая (apps/admin)
 FROM node:22-alpine AS deps
 RUN corepack enable
 WORKDIR /repo
@@ -15,13 +16,15 @@ ARG CLIENT_BOT_USERNAME=barevclub_bot
 ENV VITE_LANDING_URL=$LANDING_URL NEXT_PUBLIC_API_URL=$API_PUBLIC_URL CLIENT_BOT_USERNAME=$CLIENT_BOT_USERNAME NEXT_TELEMETRY_DISABLED=1
 RUN pnpm --filter @barev/miniapp-client build \
  && pnpm --filter @barev/miniapp-pro build \
- && pnpm --filter @barev/admin build \
+ && ADMIN_BASE=/old/ pnpm --filter @barev/admin build \
+ && VITE_OLD_ADMIN_URL=/old/ pnpm --filter @barev/backoffice build \
  && pnpm --filter @barev/landing build
 
 FROM nginx:alpine AS web
 COPY --from=build /repo/apps/miniapp-client/dist /srv/client
 COPY --from=build /repo/apps/miniapp-pro/dist /srv/pro
-COPY --from=build /repo/apps/admin/dist /srv/admin
+COPY --from=build /repo/apps/backoffice/dist /srv/admin
+COPY --from=build /repo/apps/admin/dist /srv/admin/old
 COPY infra/prod/nginx.conf /etc/nginx/conf.d/default.conf
 
 FROM node:22-alpine AS app