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/@npmcli/fs/lib/index.js

@@ -0,0 +1,13 @@
+'use strict'
+
+const cp = require('./cp/index.js')
+const withTempDir = require('./with-temp-dir.js')
+const readdirScoped = require('./readdir-scoped.js')
+const moveFile = require('./move-file.js')
+
+module.exports = {
+  cp,
+  withTempDir,
+  readdirScoped,
+  moveFile,
+}