Add changeset for extension update notification system

Author: elieteyssedou

.changeset/extension-update-notification.md

@@ -0,0 +1,11 @@
+---
+"@mcp-pointer/chrome-extension": patch
+---
+
+Add extension update notification system
+
+When the Chrome extension is updated, users now automatically see a notification page guiding them to reconfigure their MCP server for auto-updates. The notification opens at https://mcp-pointer.etsd.tech/update-notice.html and provides step-by-step instructions for enabling automatic updates with their AI tool.
+
+- Added onInstalled listener to detect extension updates
+- Added tabs permission for opening external notification page
+- Set up GitHub Pages infrastructure for update notifications