Remove vestigial docker-compose.yml

OnlyOffice setup is done entirely by mediapreview (cista --oosetup ->
mediapreview.office.setup_docker: image build, oonet network creation,
docker run). Nothing referenced this compose file; it was a leftover
from before the preview functionality moved to the mediapreview package.

docker-compose.yml

@@ -1,46 +0,0 @@
-services:
-  onlyoffice:
-    build:
-      context: ./mediapreview/mediapreview/docker
-      args:
-        ONLYOFFICE_VERSION: "9.3.1"
-    container_name: onlyoffice
-    # No published ports: Docker discards them on internal networks anyway.
-    # The host reaches the container at its fixed IP (172.30.0.2).
-    environment:
-      # Number of converter workers (default 8).
-      # Set to your CPU count or slightly below.
-      - WORKERS
-      # JWT secret shared with Cista.
-      # OnlyOffice reads it as JWT_SECRET; Cista reads it as ONLYOFFICE_JWT_SECRET.
-      # We use ONLYOFFICE_JWT_SECRET as the canonical name so you only set one variable.
-      - JWT_SECRET=${ONLYOFFICE_JWT_SECRET}
-      - JWT_ENABLED=true
-      - JWT_HEADER=Authorization
-    volumes:
-      # Persist fonts and generated caches across restarts
-      - onlyoffice-data:/var/www/onlyoffice/Data
-      - onlyoffice-lib:/var/lib/onlyoffice
-    networks:
-      # Fully isolated: no outbound internet, container can only reach the
-      # host on this bridge (needed for the preview file callback).
-      oonet:
-        # Fixed IP matching mediapreview's OO_CONTAINER_IP.
-        ipv4_address: 172.30.0.2
-    restart: unless-stopped
-
-networks:
-  oonet:
-    # Fixed name (no compose project prefix) so it matches mediapreview's
-    # OO_NETWORK and the container setup done by `cista --oosetup`.
-    name: oonet
-    internal: true
-    # Pin the subnet so the gateway (and thus the auto-detected callback
-    # host) is stable: the host is always 172.30.0.1.
-    ipam:
-      config:
-        - subnet: 172.30.0.0/24
-
-volumes:
-  onlyoffice-data:
-  onlyoffice-lib: