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/minipass-fetch/lib/fetch-error.js

@@ -0,0 +1,32 @@
+'use strict'
+class FetchError extends Error {
+  constructor (message, type, systemError) {
+    super(message)
+    this.code = 'FETCH_ERROR'
+
+    // pick up code, expected, path, ...
+    if (systemError) {
+      Object.assign(this, systemError)
+    }
+
+    this.errno = this.code
+
+    // override anything the system error might've clobbered
+    this.type = this.code === 'EBADSIZE' && this.found > this.expect
+      ? 'max-size' : type
+    this.message = message
+    Error.captureStackTrace(this, this.constructor)
+  }
+
+  get name () {
+    return 'FetchError'
+  }
+
+  // don't allow name to be overwritten
+  set name (n) {}
+
+  get [Symbol.toStringTag] () {
+    return 'FetchError'
+  }
+}
+module.exports = FetchError