Add optional outbound connectivity probe with three-state status dot

prefs.js

@@ -46,6 +46,32 @@ export default class SingBoxStatusPreferences extends ExtensionPreferences {
         });
         settings.bind('refresh-interval', intervalRow, 'value', Gio.SettingsBindFlags.DEFAULT);
         dispGroup.add(intervalRow);
+
+        // --- Connectivity ---------------------------------------------
+        const connCheckGroup = new Adw.PreferencesGroup({
+            title: _('Connectivity check'),
+            description: _('Actively probe the active outbound to tell “up but no internet” from “up and reachable”. Adds a third status-dot state.'),
+        });
+        page.add(connCheckGroup);
+
+        const checkRow = this._switchRow(settings, 'check-connectivity',
+            _('Probe active outbound'),
+            _('Periodically measure latency through the current outbound.'));
+        connCheckGroup.add(checkRow);
+
+        const connIntervalRow = new Adw.SpinRow({
+            title: _('Probe interval'),
+            subtitle: _('Seconds between outbound probes.'),
+            adjustment: new Gtk.Adjustment({ lower: 5, upper: 600, step_increment: 5 }),
+        });
+        settings.bind('connectivity-interval', connIntervalRow, 'value', Gio.SettingsBindFlags.DEFAULT);
+        settings.bind('check-connectivity', connIntervalRow, 'sensitive', Gio.SettingsBindFlags.GET);
+        connCheckGroup.add(connIntervalRow);
+
+        const connUrlRow = this._entryRow(settings, 'connectivity-url', _('Probe URL'),
+            _('Target URL for the latency probe (a 204/no-content endpoint is ideal).'));
+        settings.bind('check-connectivity', connUrlRow, 'sensitive', Gio.SettingsBindFlags.GET);
+        connCheckGroup.add(connUrlRow);
     }
 
     _entryRow(settings, key, title, subtitle) {