693 pages, 693 tests, 0 failed - all ok
Every test here fails on purpose: the strict syntax checks, the expression evaluator's
reports, the pages that end a request, and the error handler family, each answering an
expected HTTP 500 asserted by a pattern over the message. The application
declares the boot error action, so an expected failure is the lean JSON
answer - no heavy error page, nothing under DATA/dumps, and the same shape
for every requester. These cases live in apps/regression/errors/, with
_common switched off.