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/autoprefixer/lib/hacks/grid-column-align.js

@@ -0,0 +1,28 @@
+let Declaration = require('../declaration')
+
+class GridColumnAlign extends Declaration {
+  /**
+   * Do not prefix flexbox values
+   */
+  check(decl) {
+    return !decl.value.includes('flex-') && decl.value !== 'baseline'
+  }
+
+  /**
+   * Change IE property back
+   */
+  normalize() {
+    return 'justify-self'
+  }
+
+  /**
+   * Change property name for IE
+   */
+  prefixed(prop, prefix) {
+    return prefix + 'grid-column-align'
+  }
+}
+
+GridColumnAlign.names = ['grid-column-align']
+
+module.exports = GridColumnAlign