# Commands ## Backend ```sh cd backend bundle install bundle exec rails db:migrate bundle exec rspec bundle exec rails routes ``` Material video thumbnail generation requires `ffmpeg` on the host. If `ffmpeg` is missing or frame extraction fails, `MaterialThumbnailGenerator` logs the result and stderr, then leaves the existing thumbnail unchanged. ```sh cd backend bundle exec rails materials:thumbnails:backfill ``` ## Frontend ```sh cd frontend npm install npm run dev npm run build npm run lint npm run test npm run test:run ``` ### Full verification ```sh cd backend && bundle exec rspec cd ../frontend && npm run test:run && npm run build && npm run lint ```