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/gopd/test/index.js

@@ -0,0 +1,36 @@
+'use strict';
+
+var test = require('tape');
+var gOPD = require('../');
+
+test('gOPD', function (t) {
+	t.test('supported', { skip: !gOPD }, function (st) {
+		st.equal(typeof gOPD, 'function', 'is a function');
+
+		var obj = { x: 1 };
+		st.ok('x' in obj, 'property exists');
+
+		// @ts-expect-error TS can't figure out narrowing from `skip`
+		var desc = gOPD(obj, 'x');
+		st.deepEqual(
+			desc,
+			{
+				configurable: true,
+				enumerable: true,
+				value: 1,
+				writable: true
+			},
+			'descriptor is as expected'
+		);
+
+		st.end();
+	});
+
+	t.test('not supported', { skip: !!gOPD }, function (st) {
+		st.notOk(gOPD, 'is falsy');
+
+		st.end();
+	});
+
+	t.end();
+});