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/@tufjs/models/dist/key.d.ts

@@ -0,0 +1,21 @@
+import { Signable } from './base';
+import { JSONObject, JSONValue } from './utils';
+export interface KeyOptions {
+    keyID: string;
+    keyType: string;
+    scheme: string;
+    keyVal: Record<string, string>;
+    unrecognizedFields?: Record<string, JSONValue>;
+}
+export declare class Key {
+    readonly keyID: string;
+    readonly keyType: string;
+    readonly scheme: string;
+    readonly keyVal: Record<string, string>;
+    readonly unrecognizedFields?: Record<string, JSONValue>;
+    constructor(options: KeyOptions);
+    verifySignature(metadata: Signable): void;
+    equals(other: Key): boolean;
+    toJSON(): JSONObject;
+    static fromJSON(keyID: string, data: JSONObject): Key;
+}