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/readdir-scoped.js

@@ -0,0 +1,20 @@
+const { readdir } = require('fs/promises')
+const { join } = require('path')
+
+const readdirScoped = async (dir) => {
+  const results = []
+
+  for (const item of await readdir(dir)) {
+    if (item.startsWith('@')) {
+      for (const scopedItem of await readdir(join(dir, item))) {
+        results.push(join(item, scopedItem))
+      }
+    } else {
+      results.push(item)
+    }
+  }
+
+  return results
+}
+
+module.exports = readdirScoped