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/qs/.editorconfig

@@ -0,0 +1,46 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+max_line_length = 180
+quote_type = single
+
+[test/*]
+max_line_length = off
+
+[LICENSE.md]
+indent_size = off
+
+[*.md]
+max_line_length = off
+
+[*.json]
+max_line_length = off
+
+[Makefile]
+max_line_length = off
+
+[CHANGELOG.md]
+indent_style = space
+indent_size = 2
+
+[LICENSE]
+indent_size = 2
+max_line_length = off
+
+[coverage/**/*]
+indent_size = off
+indent_style = off
+indent = off
+max_line_length = off
+
+[.nycrc]
+indent_style = tab
+
+[tea.yaml]
+indent_size = 2