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/lib/util/propertyAccess.js

@@ -0,0 +1,30 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const { SAFE_IDENTIFIER, RESERVED_IDENTIFIER } = require("./propertyName");
+
+/**
+ * @param {ArrayLike<string>} properties properties
+ * @param {number} start start index
+ * @returns {string} chain of property accesses
+ */
+const propertyAccess = (properties, start = 0) => {
+	let str = "";
+	for (let i = start; i < properties.length; i++) {
+		const p = properties[i];
+		if (`${Number(p)}` === p) {
+			str += `[${p}]`;
+		} else if (SAFE_IDENTIFIER.test(p) && !RESERVED_IDENTIFIER.has(p)) {
+			str += `.${p}`;
+		} else {
+			str += `[${JSON.stringify(p)}]`;
+		}
+	}
+	return str;
+};
+
+module.exports = propertyAccess;