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/useElementSizeObserver.ts

@@ -3,7 +3,7 @@ import { getResizeObserverEntry, useResizeObserver } from './useResizeObserver';
 
 export const useElementSizeObserver = <T extends Element>(
   element: () => T | null,
-  onResize: (width: number, height: number, element: T) => void
+  onResize: (width: number, height: number, element: T) => void,
 ) => {
   useResizeObserver(
     useCallback(
@@ -16,8 +16,8 @@ export const useElementSizeObserver = <T extends Element>(
           onResize(clientWidth, clientHeight, target);
         }
       },
-      [element, onResize]
+      [element, onResize],
     ),
-    element
+    element,
   );
 };