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/postcss-value-parser/lib/index.js

@@ -0,0 +1,28 @@
+var parse = require("./parse");
+var walk = require("./walk");
+var stringify = require("./stringify");
+
+function ValueParser(value) {
+  if (this instanceof ValueParser) {
+    this.nodes = parse(value);
+    return this;
+  }
+  return new ValueParser(value);
+}
+
+ValueParser.prototype.toString = function() {
+  return Array.isArray(this.nodes) ? stringify(this.nodes) : "";
+};
+
+ValueParser.prototype.walk = function(cb, bubble) {
+  walk(this.nodes, cb, bubble);
+  return this;
+};
+
+ValueParser.unit = require("./unit");
+
+ValueParser.walk = walk;
+
+ValueParser.stringify = stringify;
+
+module.exports = ValueParser;