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/webpack-dev-server/lib/servers/BaseServer.js

@@ -0,0 +1,18 @@
+"use strict";
+
+/** @typedef {import("../Server").ClientConnection} ClientConnection */
+
+// base class that users should extend if they are making their own
+// server implementation
+module.exports = class BaseServer {
+  /**
+   * @param {import("../Server")} server
+   */
+  constructor(server) {
+    /** @type {import("../Server")} */
+    this.server = server;
+
+    /** @type {ClientConnection[]} */
+    this.clients = [];
+  }
+};