Limit container block I/O bandwidth and IOPS in Docker Compose with blkio_config (weight, device read/write bps and iops limits)

Documented steps

1. Under a service, add a `blkio_config:` map to impose block I/O limits on the container.
2. Set `weight:` to a relative bandwidth priority vs other services; valid integer range is 10-1000 and the default is 500.
3. To set a per-device weight, use `weight_device:` with `path:` (device path) and a `weight:` in 10-1000 for that device.
4. Cap throughput with `device_read_bps:` / `device_write_bps:`; each entry takes `path:` and `rate:` where rate is bytes/sec (integer bytes or a string like '10mb').
5. Cap operations with `device_read_iops:` / `device_write_iops:`; each entry takes `path:` and `rate:` where rate is operations/sec.
6. Run `docker compose up -d` and verify with `docker inspect` (HostConfig BlkioWeight / BlkioDeviceReadBps etc.).
7. Docs: https://docs.docker.com/reference/compose-file/services/#blkio_config