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/autoprefixer/bin/autoprefixer

@@ -0,0 +1,22 @@
+#!/usr/bin/env node
+
+let mode = process.argv[2]
+if (mode === '--info') {
+  process.stdout.write(require('../')().info() + '\n')
+} else if (mode === '--version') {
+  process.stdout.write(
+    'autoprefixer ' + require('../package.json').version + '\n'
+  )
+} else {
+  process.stdout.write(
+    'autoprefix\n' +
+      '\n' +
+      'Options:\n' +
+      '  --info    Show target browsers and used prefixes\n' +
+      '  --version Show version number\n' +
+      '  --help    Show help\n' +
+      '\n' +
+      'Usage:\n' +
+      '  autoprefixer --info\n'
+  )
+}