The bus refuses a stale mode revision as request-mode-revision-conflict, so the Console route maps that
code to 409 instead of request-mode-stale and request-mode-unchanged, which no bus emits. The mode copy and the
request-mode-changed wait label describe Task 4's project-level change. The draft route relays Task 4's
{ candidate, prd, requirements } reply when its candidate names the request, and maps prd-candidate-required to 409.