Fix convex by forcing downgrade of usesend-js package

packages/backend/package.json

@@ -29,7 +29,7 @@
     "convex": "catalog:convex",
     "react": "catalog:react19",
     "react-dom": "catalog:react19",
-    "usesend-js": "^1.6.3",
+    "usesend-js": "^1.5.6",
     "zod": "catalog:"
   },
   "devDependencies": {