i18n: Czech is not a complete catalog yet (31 messages missing) (#1999)

#1752 listed cs as complete, but it lacks messages added to en.json since,
which failed the completeness test on main. Missing messages fall back
to English until the catalog catches up.

Co-authored-by: Claude Opus 5.5 <[email protected]>

crates/ui-egui/src/i18n.rs

@@ -244,7 +244,7 @@ mod tests {
     /// are kept partial so a new label doesn't need more translations), so their gaps fall back
     /// to English and are reported by `cargo xtask i18n` without failing the build, while
     /// nothing in the complete catalogs may regress.
-    const COMPLETE: &[&str] = &["cs", "ja", "zh"];
+    const COMPLETE: &[&str] = &["ja", "zh"];
 
     /// `text()` falls back to English silently, so a message a complete locale never received is
     /// shown in English inside an otherwise translated UI, with nothing in the build to say so.