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/thingies/lib/codeMutex.js

@@ -0,0 +1,21 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.codeMutex = void 0;
+/**
+ * Executes only one instance of give code at a time. If other calls come in in
+ * parallel, they get resolved to the result of the ongoing execution.
+ */
+const codeMutex = () => {
+    let result;
+    return async (code) => {
+        if (result)
+            return result;
+        try {
+            return await (result = code());
+        }
+        finally {
+            result = undefined;
+        }
+    };
+};
+exports.codeMutex = codeMutex;