CI parity tests enforce that every key in the English locale block exists
in zh, ja, ko, ru, and es. The PR introducing download_folder added it to
en only, which broke the 5 hard-parity test files. Adds the English
fallback to all 10 non-en blocks (it/ja/ru/es/de/zh/zh-Hant/pt/ko/fr) with
the project's // TODO: translate marker so translators can refine later.
Tests: tests/test_chinese_locale.py, test_japanese_locale.py,
test_korean_locale.py, test_russian_locale.py, test_spanish_locale.py —
26/26 passing locally.
b1b93f9c97
