Initial commit: notification-elements-demo app

Interactive Angular 19 demo for @sda/notification-elements-ui with
6 sections: Bell & Feed, Notification Center, Inbox, Comments &
Threads, Mention Input, and Full-Featured layout. Includes mock
data, dark mode toggle, and real-time event log.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

node_modules/resolve-url-loader/lib/join-function/fs-utils.js

@@ -0,0 +1,24 @@
+/*
+ * MIT License http://opensource.org/licenses/MIT
+ * Author: Ben Holloway @bholloway
+ */
+'use strict';
+
+const fsUtils = (fs) => {
+  // fs from enhanced-resolver doesn't include fs.existsSync so we need to use fs.statsSync instead
+  const withStats = (fn) => (absolutePath) => {
+    try {
+      return fn(fs.statSync(absolutePath));
+    } catch (e) {
+      return false;
+    }
+  };
+
+  return {
+    isFileSync: withStats((stats) => stats.isFile()),
+    isDirectorySync: withStats((stats) => stats.isDirectory()),
+    existsSync: withStats((stats) => stats.isFile() || stats.isDirectory())
+  };
+};
+
+module.exports = fsUtils;