Sparkle fixes

scripts/build_release.sh

@@ -36,6 +36,11 @@ generate_appcast() {
     download_prefix="${SPARKLE_DOWNLOAD_BASE_URL%/}/v${VERSION}"
   fi
 
+  # Ensure the version segment is present to match Gitea's /download/vX.Y.Z/ layout.
+  if [[ -n "$download_prefix" ]] && [[ "$download_prefix" != *"/$VERSION"* ]]; then
+    download_prefix="${download_prefix%/}/v${VERSION}"
+  fi
+
   if [[ -z "$generator" || -z "${SPARKLE_EDDSA_KEY_FILE:-}" || -z "$download_prefix" ]]; then
     echo "ℹ️ Skipping Sparkle appcast generation (generator/key/download prefix not configured)."
     return