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/@jsonjoy.com/fs-node/lib/index.d.ts

@@ -0,0 +1,16 @@
+export { Volume, StatWatcher, FSWatcher, toUnixTimestamp } from './volume';
+export type { IWriteStream, IError, IAppendFileOptions, IWatchFileOptions, IWatchOptions } from './volume';
+export { default as Stats, TStatNumber } from './Stats';
+export { default as Dirent } from './Dirent';
+export { default as StatFs } from './StatFs';
+export { FileHandle } from './FileHandle';
+export { Dir } from './Dir';
+export { FsPromises } from './FsPromises';
+export * from './options';
+export * from './util';
+export * from './glob';
+export { fsCallbackApiList } from './lists/fsCallbackApiList';
+export { fsSynchronousApiList } from './lists/fsSynchronousApiList';
+export { fsCommonObjectsList } from './lists/fsCommonObjectsList';
+export type { FsCommonObjects } from './types/FsCommonObjects';
+export type { FsPromisesApi } from './types/FsPromisesApi';