LocaleStore.Load silently skips a *.json that fails to parse, so a broken
de.json left store.Available with only "en" and the parity loop compared
English against itself, always green. Add two guards before the loop:
loaded-locale count must match the number of *.json files in the folder,
and "de" must be present via TryGet, both with failure messages naming the
missing file. Also independently JsonDocument.Parse every *.json so a
syntax error surfaces as a syntax error with the file name, not as
"locale missing". LocaleStore's catch-and-skip is untouched -- a broken
translation must still not crash the app at runtime.
Mika Kuns
4c78a5d6fd