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/process-nextick-args/index.js

@@ -0,0 +1,45 @@
+'use strict';
+
+if (typeof process === 'undefined' ||
+    !process.version ||
+    process.version.indexOf('v0.') === 0 ||
+    process.version.indexOf('v1.') === 0 && process.version.indexOf('v1.8.') !== 0) {
+  module.exports = { nextTick: nextTick };
+} else {
+  module.exports = process
+}
+
+function nextTick(fn, arg1, arg2, arg3) {
+  if (typeof fn !== 'function') {
+    throw new TypeError('"callback" argument must be a function');
+  }
+  var len = arguments.length;
+  var args, i;
+  switch (len) {
+  case 0:
+  case 1:
+    return process.nextTick(fn);
+  case 2:
+    return process.nextTick(function afterTickOne() {
+      fn.call(null, arg1);
+    });
+  case 3:
+    return process.nextTick(function afterTickTwo() {
+      fn.call(null, arg1, arg2);
+    });
+  case 4:
+    return process.nextTick(function afterTickThree() {
+      fn.call(null, arg1, arg2, arg3);
+    });
+  default:
+    args = new Array(len - 1);
+    i = 0;
+    while (i < args.length) {
+      args[i++] = arguments[i];
+    }
+    return process.nextTick(function afterTick() {
+      fn.apply(null, args);
+    });
+  }
+}
+