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/mimic-fn/index.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const mimicFn = (to, from) => {
+	for (const prop of Reflect.ownKeys(from)) {
+		Object.defineProperty(to, prop, Object.getOwnPropertyDescriptor(from, prop));
+	}
+
+	return to;
+};
+
+module.exports = mimicFn;
+// TODO: Remove this for the next major release
+module.exports.default = mimicFn;