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/ajv/dist/runtime/parseJson.d.ts

@@ -0,0 +1,18 @@
+export declare function parseJson(s: string, pos: number): unknown;
+export declare namespace parseJson {
+    var message: string | undefined;
+    var position: number;
+    var code: string;
+}
+export declare function parseJsonNumber(s: string, pos: number, maxDigits?: number): number | undefined;
+export declare namespace parseJsonNumber {
+    var message: string | undefined;
+    var position: number;
+    var code: string;
+}
+export declare function parseJsonString(s: string, pos: number): string | undefined;
+export declare namespace parseJsonString {
+    var message: string | undefined;
+    var position: number;
+    var code: string;
+}