Website restoration: Node.js backend, restored design, GitHub sync disabled

- Replaced broken .NET backend with Node.js/Express
- Restored original website design with purple gradient hero
- Updated homepage and shop pages with Bootstrap 5 responsive design
- Disabled GitHub remote sync - all code now stored locally only
- Created backup scripts and documentation
- All changes saved on Ubuntu server at /var/www/SkyArtShop

backend/node_modules/lodash/_stackHas.js

@@ -0,0 +1,14 @@
+/**
+ * Checks if a stack value for `key` exists.
+ *
+ * @private
+ * @name has
+ * @memberOf Stack
+ * @param {string} key The key of the entry to check.
+ * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+ */
+function stackHas(key) {
+  return this.__data__.has(key);
+}
+
+module.exports = stackHas;