With a Chinese UI on Windows and macOS, the first CJK fallback was a Japanese font without the simplified characters, so one word mixed glyphs from two faces with different line heights and they sat on different baselines. For zh the Chinese face now joins the fallback chain before the Japanese one, and the chain is rebuilt on the frame the UI language changes; other languages keep the previous order.
Adds a complete Simplified Chinese (zh) catalog covering every English message, a font fallback for Chinese text, and `cargo xtask i18n --check`, which checks that the complete catalogs (ja, zh) carry every English message and that every command label is translatable.
Co-authored-by: Noly1990 <20500931+Noly1990@users.noreply.github.com>
Noly