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/components/Pdf-viewer/PdfViewer.tsx

@@ -43,7 +43,7 @@ export const PdfViewer = as<'div', PdfViewerProps>(
     const [pdfJSState, loadPdfJS] = usePdfJSLoader();
     const [docState, loadPdfDocument] = usePdfDocumentLoader(
       pdfJSState.status === AsyncStatus.Success ? pdfJSState.data : undefined,
-      src
+      src,
     );
     const isLoading =
       pdfJSState.status === AsyncStatus.Loading || docState.status === AsyncStatus.Loading;
@@ -257,5 +257,5 @@ export const PdfViewer = as<'div', PdfViewerProps>(
         )}
       </Box>
     );
-  }
+  },
 );