Add big_sale_inject.js loader for dynamic CSS/JS injection

big_sale_inject.js

@@ -0,0 +1,22 @@
+// BIG SALE Injector - loads CSS and JS dynamically
+// This file is loaded from index.html via: <script defer src="./big_sale_inject.js?v=1"></script>
+(function() {
+  var css = document.createElement('link');
+  css.rel = 'stylesheet';
+  css.href = './big_sale.css?v=2';
+  document.head.appendChild(css);
+
+  var js = document.createElement('script');
+  js.defer = true;
+  js.src = './big_sale.js?v=2';
+  js.onload = function() {
+    if (typeof initBigSale === 'function') {
+      initBigSale();
+    } else {
+      setTimeout(function() { if (typeof initBigSale === 'function') initBigSale(); }, 500);
+    }
+  };
+  document.body.appendChild(js);
+
+  console.log('[BIG SALE] Injector loaded');
+})();