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/log-symbols/index.js

@@ -0,0 +1,19 @@
+'use strict';
+const chalk = require('chalk');
+const isUnicodeSupported = require('is-unicode-supported');
+
+const main = {
+	info: chalk.blue('ℹ'),
+	success: chalk.green('✔'),
+	warning: chalk.yellow('⚠'),
+	error: chalk.red('✖')
+};
+
+const fallback = {
+	info: chalk.blue('i'),
+	success: chalk.green('√'),
+	warning: chalk.yellow('‼'),
+	error: chalk.red('×')
+};
+
+module.exports = isUnicodeSupported() ? main : fallback;