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/add.js

@@ -0,0 +1,22 @@
+var createMathOperation = require('./_createMathOperation');
+
+/**
+ * Adds two numbers.
+ *
+ * @static
+ * @memberOf _
+ * @since 3.4.0
+ * @category Math
+ * @param {number} augend The first number in an addition.
+ * @param {number} addend The second number in an addition.
+ * @returns {number} Returns the total.
+ * @example
+ *
+ * _.add(6, 4);
+ * // => 10
+ */
+var add = createMathOperation(function(augend, addend) {
+  return augend + addend;
+}, 0);
+
+module.exports = add;