Add dev init script with auto-created admin user (admin/admin) on first boot

dev/docker-compose.yml

@@ -46,12 +46,13 @@ services:
       MM_ANNOUNCEMENTSETTINGS_ADMINNOTICESENABLED: "false"
     ports:
       - "8065:8065"
+    # Auto-create admin user (admin/admin) on first boot.
+    entrypoint: ["/bin/bash", "/init.sh"]
     volumes:
-      # Persistent plugin directory — mount the dist folder so you can
-      # upload plugins via UI or copy them directly:
+      # Init script creates admin user on first startup.
+      - ./init.sh:/init.sh:ro
+      # Plugin directory — mount so you can upload via UI:
       - ./mattermost/plugins:/mattermost/data/plugins:rw
-      # Config override (optional — uncomment to persist config changes)
-      # - ./mattermost/config:/mattermost/config:rw
       # Data volume for uploads, avatars, etc.
       - mattermost-data:/mattermost/data:rw
     healthcheck: