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/upload-board/UploadBoard.tsx

@@ -59,14 +59,14 @@ export function UploadBoardHeader({
       }
       return acc;
     },
-    { loaded: 0, total: 0 }
+    { loaded: 0, total: 0 },
   );
 
   const handleSend = async () => {
     if (sendingRef.current) return;
     sendingRef.current = true;
     await onSend(
-      uploads.filter((upload) => upload.status === UploadStatus.Success) as UploadSuccess[]
+      uploads.filter((upload) => upload.status === UploadStatus.Success) as UploadSuccess[],
     );
     sendingRef.current = false;
   };