fix(settings): keep the language and save settings one after the other

README.md

@@ -67,6 +67,8 @@ To Be Played is split into three repositories:
   ("Profile art" on a game's page). Visitors see the owner's look on that page only; light or dark mode stays theirs.
 - **Appearance**: accent color, corner style, wide layout, page background and banner from your own game art.
   Saved in Auth, so it follows you to every device.
+- **Language**: kept in the browser and saved in Auth; after the login Auth's language wins when one is saved. Dark
+  mode stays per device.
 - **Broken pictures**: a Steam cover or achievement icon that does not load shows a placeholder and is reported
   to Core once per page load (`POST /api/library/broken-images`, only with a session). Core repairs it at night;
   a repaired cover comes back as `imageUrl`.
@@ -130,6 +132,10 @@ flowchart LR
 - `src/utils/brokenImages.js` reports pictures that fail to load (`GameCover`, achievement icons on the game
   detail page) to Core.
 - `useLibrarySync` polls Core's `/api/library/sync-status` while a Steam sync runs, then loads the data again.
+- `PUT /api/users/settings` replaces dark mode, language, display name and public profile at once, so every save
+  goes through `saveSettings` in `src/utils/settings.js`: one after the other, each on a fresh `GET /api/users/me`.
+- Pages keep a load error as its i18n key and translate it when rendering, so a language switch loads nothing
+  again.
 
 ## Project structure