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/declarations/index.d.ts

@@ -0,0 +1,19 @@
+export type Schema = import("./validate").Schema;
+export type JSONSchema4 = import("./validate").JSONSchema4;
+export type JSONSchema6 = import("./validate").JSONSchema6;
+export type JSONSchema7 = import("./validate").JSONSchema7;
+export type ExtendedSchema = import("./validate").ExtendedSchema;
+export type ValidationErrorConfiguration =
+  import("./validate").ValidationErrorConfiguration;
+import { validate } from "./validate";
+import { ValidationError } from "./validate";
+import { enableValidation } from "./validate";
+import { disableValidation } from "./validate";
+import { needValidate } from "./validate";
+export {
+  validate,
+  ValidationError,
+  enableValidation,
+  disableValidation,
+  needValidate,
+};