fix: add tabs permission for background script injection

Added 'tabs' permission to enable the background script to inject
content scripts into existing GitHub tabs when the extension is
installed or updated. This ensures the extension works on already
open tabs without requiring a page reload.

Author: yamadashy

wxt.config.ts

@@ -6,7 +6,7 @@ export default defineConfig({
     version: '1.0.0',
     description: '__MSG_appDescription__',
     default_locale: 'en',
-    permissions: ['scripting'],
+    permissions: ['scripting', 'tabs'],
     host_permissions: ['https://github.com/*'],
     icons: {
       16: '/images/icon-16.png',