Add an active e2e spec asserting /briefwechsel 404s on the styled app
error page. The old assertion lived in stammbaum.spec.ts inside a
test.skip() block (never executed) and asserted the opposite — remove it.
Drop /briefwechsel from the auth protected-route loop; /documents (the
redirect target) sits behind the same authenticated() rule, so coverage
is preserved.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>