add firefox extension id

extension/wxt.config.ts

···
           default_title: 'Margin',
           default_panel: 'sidepanel.html',
         },
+        browser_specific_settings: {
+          gecko: {
+            id: '[e-mail]',
+            strict_min_version: '109.0',
+          },
+        },
       }),
     };
   },