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/mkdirp/lib/path-arg.js

@@ -0,0 +1,29 @@
+const platform = process.env.__TESTING_MKDIRP_PLATFORM__ || process.platform
+const { resolve, parse } = require('path')
+const pathArg = path => {
+  if (/\0/.test(path)) {
+    // simulate same failure that node raises
+    throw Object.assign(
+      new TypeError('path must be a string without null bytes'),
+      {
+        path,
+        code: 'ERR_INVALID_ARG_VALUE',
+      }
+    )
+  }
+
+  path = resolve(path)
+  if (platform === 'win32') {
+    const badWinChars = /[*|"<>?:]/
+    const {root} = parse(path)
+    if (badWinChars.test(path.substr(root.length))) {
+      throw Object.assign(new Error('Illegal characters in path.'), {
+        path,
+        code: 'EINVAL',
+      })
+    }
+  }
+
+  return path
+}
+module.exports = pathArg