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/features/common-settings/developer-tools/DevelopTools.tsx

@@ -60,7 +60,7 @@ export function DeveloperTools({ requestClose }: DeveloperToolsProps) {
     async (type, content) => {
       await mx.setRoomAccountData(room.roomId, type, content);
     },
-    [mx, room.roomId]
+    [mx, room.roomId],
   );
 
   if (accountDataType !== undefined) {