Harden release upload scripts

scripts/upload-gitea-release.sh

@@ -102,6 +102,7 @@ delete_existing_asset() {
     done
 }
 
+uploaded=0
 for artifact in "$@"; do
   if [ ! -f "$artifact" ]; then
     continue
@@ -114,4 +115,10 @@ for artifact in "$@"; do
     -X POST \
     -F "attachment=@$artifact" \
     "$api/releases/$release_id/assets?name=$name" >/dev/null
+  uploaded=$((uploaded + 1))
 done
+
+if [ "$uploaded" -eq 0 ]; then
+  echo "no release artifacts uploaded" >&2
+  exit 1
+fi