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/npm-registry-fetch/lib/default-opts.js

@@ -0,0 +1,19 @@
+const pkg = require('../package.json')
+module.exports = {
+  maxSockets: 12,
+  method: 'GET',
+  registry: 'https://registry.npmjs.org/',
+  timeout: 5 * 60 * 1000, // 5 minutes
+  strictSSL: true,
+  noProxy: process.env.NOPROXY,
+  userAgent: `${pkg.name
+    }@${
+      pkg.version
+    }/node@${
+      process.version
+    }+${
+      process.arch
+    } (${
+      process.platform
+    })`,
+}