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/@babel/helper-define-polyfill-provider/lib/browser/dependencies.js

@@ -0,0 +1,22 @@
+"use strict";
+
+exports.__esModule = true;
+exports.has = has;
+exports.laterLogMissing = laterLogMissing;
+exports.logMissing = logMissing;
+exports.resolve = resolve;
+function resolve(dirname, moduleName, absoluteImports) {
+  if (absoluteImports === false) return moduleName;
+  throw new Error(`"absoluteImports" is not supported in bundles prepared for the browser.`);
+}
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+function has(basedir, name) {
+  return true;
+}
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+function logMissing(missingDeps) {}
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+function laterLogMissing(missingDeps) {}