docker-compose for Next.js + NestJS local dev

Most docker-compose tutorials for Next.js stop at "here's a service block, here's how to mount your code." Then you start it on macOS, type a character in your editor, and hot reload doesn't fire. You add a Postgres service, your NestJS API tries to connect before the database is ready, and the container crashes on first boot. You stop the stack, your node_modules is mysteriously empty on the host. None of these are mysteries — they're all known issues with known fixes. Here's the docker-compose