black-box-testing

Moving Go tests into a central tree as external _test packages forces rewrites through the public API, deletes dead helpers, and coverage rises.

TL;DR: Moving sixteen test files into a central tree looked purely mechanical, yet coverage rose instead of staying flat. Renaming packages to entityadmin_test forced black-box testing through public APIs, exposing dead helpers and internal-only tests along the way. Now _test packages are my default, export_test.go stays an emergency valve, and "mechanical" commit messages get more skepticism.