[client] Raise the wasm size limit to 64 MB

The post-quantum exchange adds about 270 KB to the wasm client, pushing
it past 60 MB. ML-KEM runs in the browser too, so the code stays in.

.github/workflows/wasm-build-validation.yml

@@ -66,7 +66,7 @@ jobs:
 
           echo "Size: ${SIZE} bytes (${SIZE_MB} MB)"
 
-          if [ ${SIZE} -gt 62914560 ]; then
-            echo "Wasm binary size (${SIZE_MB}MB) exceeds 60MB limit!"
+          if [ ${SIZE} -gt 67108864 ]; then
+            echo "Wasm binary size (${SIZE_MB}MB) exceeds 64MB limit!"
             exit 1
           fi