🐛 fix(base.Dockerfile): remove unnecessary copy of ./src/backend directory to improve build performance

✨ feat(base.Dockerfile): add healthcheck for queue and celeryworker services to ensure their availability
✨ feat(docker-compose.yml): add healthcheck for queue, celeryworker, and flower services to ensure their availability
🐛 fix(docker-compose.yml): fix the path in the command for backend service startup
🐛 fix(flower.env): add missing double quote at the end of C_FORCE_ROOT value
🐛 fix(startup-backend.sh): remove unnecessary --reload flag from uvicorn command and add --workers -1 flag to utilize all available CPU cores