chore: upgrade i18next 26, prettier 3, fontsource-variable, domhandler 6, lint-staged 17

- i18next 23->26 + react-i18next 15->17
- prettier 2->3, reformat all files
- replace @fontsource/inter with @fontsource-variable/inter 5, update import path
- domhandler 5->6 (aligns with transitive deps)
- lint-staged 16->17

src/app/hooks/useGetRoom.ts

@@ -22,7 +22,7 @@ export const useGetRoom = (rooms: Set<string>): GetRoomCallback => {
       }
       return undefined;
     },
-    [mx, rooms]
+    [mx, rooms],
   );
 
   return getRoom;