The parity test joined raw fragments, which no longer matches now that
the English output clause carries a language token; it substitutes the
expected name from a literal map instead of from the module under test.
Adds the contract test: which body each locale composes, that its own
language is named, that its own translated directive is present and
last, that no German reaches a non-German prompt, and that no two
locales collapse to the same prompt. What it cannot show - whether the
prose reads well in the four languages - is stated in the file.