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/useRoomCreators.ts

@@ -32,7 +32,7 @@ export const useRoomCreators = (room: Room): Set<string> => {
 
   const creators = useMemo(
     () => (createEvent ? getRoomCreators(createEvent) : new Set<string>()),
-    [createEvent]
+    [createEvent],
   );
 
   return creators;