Add build pipeline for every pull-request that is open

- must successfully compile the project
- must successfully run all the tests
- must successfully build the project on prod environment

Start by inspecting the repository's existing build, test, and production-environment configuration; the issue does not name specific files or entry points. Define the pull-request pipeline around successful compilation, all tests passing, and a successful production-environment build. Done means each check runs for every open pull request and reports its result.

Written by the indexing model from the issue text.