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/schema-utils/dist/index.js

@@ -0,0 +1,23 @@
+"use strict";
+
+/** @typedef {import("./validate").Schema} Schema */
+/** @typedef {import("./validate").JSONSchema4} JSONSchema4 */
+/** @typedef {import("./validate").JSONSchema6} JSONSchema6 */
+/** @typedef {import("./validate").JSONSchema7} JSONSchema7 */
+/** @typedef {import("./validate").ExtendedSchema} ExtendedSchema */
+/** @typedef {import("./validate").ValidationErrorConfiguration} ValidationErrorConfiguration */
+
+const {
+  validate,
+  ValidationError,
+  enableValidation,
+  disableValidation,
+  needValidate
+} = require("./validate");
+module.exports = {
+  validate,
+  ValidationError,
+  enableValidation,
+  disableValidation,
+  needValidate
+};