Improve theme and navigation IPC between pages

Enhanced inter-process communication for theme updates and navigation between home, settings, and main browser pages. Theme changes in settings now propagate to home via Electron IPC and postMessage fallback. Navigation requests from home and other webviews are handled more robustly, supporting both Electron IPC and postMessage. Also refactored tab creation and improved event handling for better reliability.

renderer/customization.js

@@ -478,10 +478,13 @@ class BrowserCustomizer {
 
   applyThemeToPages() {
     // This will be called to apply theme to home.html and other pages
-    // We'll store the theme and let other pages load it
     this.saveTheme();
-    
-    // If we have access to other windows/frames, apply there too
+
+    // Send theme update to host (for settings webview)
+    if (window.electronAPI && typeof window.electronAPI.sendToHost === 'function') {
+      window.electronAPI.sendToHost('theme-update', this.currentTheme);
+    }
+    // Fallback: send via postMessage (for iframe embedding)
     try {
       if (window.parent && window.parent !== window) {
         window.parent.postMessage({