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/room/CommandAutocomplete.tsx

@@ -43,7 +43,7 @@ export function CommandAutocomplete({
   const [result, search, resetSearch] = useAsyncSearch(
     commandNames,
     useCallback((commandName: string) => commandName, []),
-    SEARCH_OPTIONS
+    SEARCH_OPTIONS,
   );
 
   const autoCompleteNames = result ? result.items : commandNames;