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/unicorn-magic/default.js

@@ -0,0 +1,14 @@
+export async function delay({seconds, milliseconds} = {}) {
+	let duration;
+	if (typeof seconds === 'number') {
+		duration = seconds * 1000;
+	} else if (typeof milliseconds === 'number') {
+		duration = milliseconds;
+	} else {
+		throw new TypeError('Expected an object with either `seconds` or `milliseconds`.');
+	}
+
+	return new Promise(resolve => {
+		setTimeout(resolve, duration);
+	});
+}