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/istanbul-lib-instrument/README.md

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+## istanbul-lib-instrument
+
+[![Build Status](https://travis-ci.org/istanbuljs/istanbul-lib-instrument.svg?branch=main)](https://travis-ci.org/istanbuljs/istanbul-lib-instrument)
+
+Istanbul instrumenter library.
+
+Version 1.1.x now implements instrumentation using `Babel`. The implementation is inspired
+by prior art by @dtinth as demonstrated in the `__coverage__` babel plugin.
+
+It provides 2 "modes" of instrumentation.
+
+-   The old API that is mostly unchanged (except for incompatibilities noted) and
+    performs the instrumentation using babel as a library.
+
+-   A `programVisitor` function for the Babel AST that can be used by a Babel plugin
+    to emit instrumentation for ES6 code directly without any source map
+    processing. This is the preferred path for babel users. The Babel plugin is
+    called `babel-plugin-istanbul`.
+
+Incompatibilities and changes to instrumentation behavior can be found in
+[v0-changes.md](v0-changes.md).
+