docs: use Docker Compose plugin command in setup guide

[zrh805]

Summary

• update the setup guide to use the Docker Compose plugin command
• apply the correction to every executable startup example in the page while keeping docker-compose.yml file references unchanged

Closes #1380

Verification

• git diff --check
• confirmed the page has no remaining docker-compose up examples

Notes

I attempted yarn build, but the local documentation dependencies were absent and yarn install --frozen-lockfile stalled during package download with no error output.