chore: update translation guidance, only en.json needs editing

CONTRIBUTING.md

@@ -57,7 +57,7 @@ npm run format       # format the code with Prettier
 ## Guidelines
 
 - Follow the existing code style. The frontend uses React, Tailwind CSS and shadcn components in `src/ui/`.
-- Never hardcode text. Use `t()` and add the English string to `src/ui/locales/en.json`. Other languages are translated on [Crowdin](https://docs.termix.site/translations).
+- Never hardcode text. Use `t()` and add the English string to `src/ui/locales/en.json`. That's the only locale file you need to update. Other languages are translated automatically, and if an automatic translation is wrong you can fix it in that language's file.
 - Keep the UI flat and square. Avoid rounded corners on panels, cards and dialogs.
 - Use the theme variables (like `var(--bg-base)` and `var(--text-primary)`) instead of fixed colors.
 - There is one component tree for desktop and mobile. Use `src/ui/hooks/use-mobile.ts` for layout changes.

src/ui/locales/README.md

@@ -1,3 +1,5 @@
-# Do Not Edit Translated Files
+# Translations
 
-Only `en.json` is edited by hand. Every other file here is translated through Crowdin and will be overwritten. See the [docs](https://docs.termix.site/translations) to help translate.
+Only `en.json` needs to be updated. Every other language in `translated/` is filled in automatically for any string that doesn't have a translation yet.
+
+If an automatic translation is wrong, fix it in that language's file. Strings that already have a translation are never overwritten.