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/useMutationObserver.ts

@@ -4,17 +4,17 @@ export type OnMutationCallback = (mutations: MutationRecord[]) => void;
 
 export const getMutationRecord = (
   target: Node,
-  mutations: MutationRecord[]
+  mutations: MutationRecord[],
 ): MutationRecord | undefined => mutations.find((mutation) => mutation.target === target);
 
 export const useMutationObserver = (
   onMutationCallback: OnMutationCallback,
   observeElement?: Node | null | (() => Node | null),
-  options?: MutationObserverInit
+  options?: MutationObserverInit,
 ): MutationObserver => {
   const mutationObserver = useMemo(
     () => new MutationObserver(onMutationCallback),
-    [onMutationCallback]
+    [onMutationCallback],
   );
 
   useEffect(() => () => mutationObserver?.disconnect(), [mutationObserver]);