flutter/packages ? reverse-engineered prompt

Build me a Flutter packages workspace that looks like the official Flutter team packages repo.

I want a clean monorepo for a set of first party Dart and Flutter packages, with a shared setup for analysis, formatting, tests, and release style checks. It should include a packages folder where each package can live on its own, plus the usual repo scripts and CI support so the packages can be developed and published in a consistent way. Please make it feel like a real maintained open source repo, with documentation in the root README, contribution guidance, and enough structure that new packages can be added without a lot of extra setup.

If you need to look up current Flutter package conventions or docs online, go ahead and use the latest guidance. Focus on making the repo pleasant to work in, easy to test, and ready for ongoing package maintenance.