Implement system status and update functionality

- Add system status card to dashboard with uptime and version display
- Implement version checking against git repository
- Add one-click update functionality
- Update footer and version references to 2.0.0
- Add server endpoints for status, update checking, and update application

🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>

public/js/app.js

@@ -41,6 +41,11 @@ function initializeApp() {
   
   // Initialize notifications system
   initNotifications();
+  
+  // Initialize system status (new in v2.0.0)
+  if (typeof initSystemStatus === 'function') {
+    initSystemStatus();
+  }
 }
 
 /**