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/make-fetch-happen/lib/cache/key.js

@@ -0,0 +1,17 @@
+const { URL, format } = require('url')
+
+// options passed to url.format() when generating a key
+const formatOptions = {
+  auth: false,
+  fragment: false,
+  search: true,
+  unicode: false,
+}
+
+// returns a string to be used as the cache key for the Request
+const cacheKey = (request) => {
+  const parsed = new URL(request.url)
+  return `make-fetch-happen:request-cache:${format(parsed, formatOptions)}`
+}
+
+module.exports = cacheKey