Added various NPM scripts.

npm/npm-install/download_package.sh

@@ -0,0 +1,65 @@
+#!/bin/bash
+set -e
+
+PACKAGE_NAME="$1"
+VERSION="$2"
+REGISTRY="$3"
+AUTH_TOKEN="$4"
+OUTPUT_DIR="${5:-.}"
+
+if [[ ! -f "$GITHUB_OUTPUT" ]]; then
+    GITHUB_OUTPUT="/dev/fd/1"
+fi
+
+# Ensure version is provided
+if [[ -z "$VERSION" ]]; then
+    echo "Error: VERSION is required"
+    exit 1
+fi
+
+# Download the tarball
+TARBALL_URL="$REGISTRY/$PACKAGE_NAME/-/$PACKAGE_NAME-$VERSION.tgz"
+TGZ_NAME="$PACKAGE_NAME-$VERSION.tgz"
+mkdir -p "$OUTPUT_DIR"
+TGZ_PATH="$OUTPUT_DIR/$TGZ_NAME"
+
+echo "Downloading $TARBALL_URL"
+CURL_HEADERS=()
+if [[ -n "$AUTH_TOKEN" ]]; then
+    CURL_HEADERS+=(-H "Authorization: Bearer $AUTH_TOKEN")
+fi
+
+# Download and capture HTTP status separately
+# Temporarily disable 'exit on error' to capture status
+set +e
+HTTP_CODE=$(curl -sL -w "%{http_code}" -o "$TGZ_PATH" "${CURL_HEADERS[@]}" "$TARBALL_URL")
+CURL_EXIT=$?
+set -e
+
+# Check if curl command itself failed (network issues, DNS, etc)
+if [[ $CURL_EXIT -ne 0 ]]; then
+    echo "Error: curl failed with exit code $CURL_EXIT (network error or invalid URL)"
+    rm -f "$TGZ_PATH"
+    exit 1
+fi
+
+# Check HTTP status code
+if [[ "$HTTP_CODE" != "200" ]]; then
+    echo "Error: Failed to download package (HTTP $HTTP_CODE)"
+    if [[ -f "$TGZ_PATH" ]]; then
+        echo "Response preview:"
+        head -c 500 "$TGZ_PATH"
+        echo ""
+        rm -f "$TGZ_PATH"
+    fi
+    exit 1
+fi
+
+if [[ ! -f "$TGZ_PATH" ]]; then
+    echo "Error: Download failed - file not created"
+    exit 1
+fi
+
+echo "tgz=$TGZ_PATH" >> "$GITHUB_OUTPUT"
+
+echo "Downloaded $TGZ_NAME"