update changelog

Author: yujonglee

apps/web/content/changelog/1.0.0-nightly.21.mdx

@@ -2,10 +2,15 @@
 created: "2025-12-16T00:00:00Z"
 ---
 
+## Notification
+
+- Fix handlers for notification events.
+
 ## Window
 
 - Window size is now decided based on the screen size.
 - Window position and size are now persisted across restarts.
+- Traffic lights are now positioned correctly across different macOS versions.
 
 ## Others