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/chardet/lib/encoding/index.d.ts

@@ -0,0 +1,14 @@
+import type { EncodingName, Match } from '../match';
+export interface Recogniser {
+    match(input: Context): Match | null;
+    name(input?: Context): EncodingName;
+    language?(): string | undefined;
+}
+export interface Context {
+    byteStats: number[];
+    c1Bytes: boolean;
+    rawInput: Uint8Array;
+    rawLen: number;
+    inputBytes: Uint8Array;
+    inputLen: number;
+}