peer-proxy: add macOS native handler

macOS routes through MethodChannel → Swift → MobileSetPeerShareEnabled
(gomobile-bind) rather than the FFI path that Windows + Linux use.
The previous review fix gated the toggle to PlatformUtils.isFFISupported
to avoid a MissingPluginException on macOS, but per Phase 1 plan macOS
should be supported.

* macos/Runner/Handlers/MethodHandler.swift: new setPeerProxyEnabled
  case + setPeerProxyEnabled function calling MobileSetPeerShareEnabled,
  plus an isPeerProxyEnabled case calling MobileIsPeerShareEnabled.
  Mirrors the existing setBlockAdsEnabled handler exactly. (The
  MobileSet/IsPeerShareEnabled gomobile bindings come from the
  SetPeerShareEnabled / IsPeerShareEnabled methods added to
  lantern-core/mobile/mobile.go in PR 8729; the Liblantern xcframework
  needs a rebuild via `make macos-framework` to pick them up.)

* lantern_platform_service.dart: restore the MethodChannel passthrough
  for setPeerProxyEnabled / isPeerProxyEnabled. The "not supported on
  this platform" stubs from the prior review fix are no longer
  appropriate now that there's a native handler.

* vpn_setting.dart: widen the toggle gate from isFFISupported (Windows
  + Linux) to isDesktop (Windows + Linux + macOS).

* radiance_settings_providers.dart: same widening for the
  isPeerProxyEnabled probe in _refresh.

Verified locally: `make macos-framework` rebuilds successfully and
exports MobileSetPeerShareEnabled / MobileIsPeerShareEnabled.
flutter analyze clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Adam Fisk

lib/features/home/provider/radiance_settings_providers.dart

@@ -30,9 +30,10 @@ class RadianceSettings extends _$RadianceSettings {
     final telemetryF = svc.isTelemetryEnabled();
     final splitF = PlatformUtils.isIOS ? null : svc.isSplitTunnelingEnabled();
     // Peer-proxy probe runs only on platforms with native handlers
-    // (FFI-supported = Windows + Linux). On other platforms the call would
-    // fail with MissingPluginException on every settings init.
-    final peerF = PlatformUtils.isFFISupported ? svc.isPeerProxyEnabled() : null;
+    // (Windows + Linux via FFI, macOS via MethodChannel — i.e. all desktop).
+    // On iOS / Android the call would fail with MissingPluginException on
+    // every settings init.
+    final peerF = PlatformUtils.isDesktop ? svc.isPeerProxyEnabled() : null;
 
     final results = await Future.wait([
       blockAdsF,

lib/features/setting/vpn_setting.dart

@@ -120,7 +120,7 @@ class VPNSetting extends HookConsumerWidget {
             },
           ),
         ),
-        if (PlatformUtils.isFFISupported) ...{
+        if (PlatformUtils.isDesktop) ...{
           SizedBox(height: 16),
           AppCard(
             padding: EdgeInsets.zero,

lib/lantern/lantern_platform_service.dart

@@ -288,21 +288,28 @@ class LanternPlatformService implements LanternCoreService {
     }
   }
 
-  // Peer-proxy has no native MethodChannel handler outside the FFI path.
-  // The toggle is gated to PlatformUtils.isFFISupported in the UI, so these
-  // implementations exist for interface conformance only and return a clear
-  // error rather than a MissingPluginException if ever invoked.
   @override
   Future<Either<Failure, Unit>> setPeerProxyEnabled(bool enabled) async {
-    return Left(Failure(
-      error: 'peer-proxy not supported on this platform',
-      localizedErrorMessage: 'peer-proxy not supported on this platform',
-    ));
+    try {
+      await _methodChannel.invokeMethod('setPeerProxyEnabled', {
+        'enabled': enabled,
+      });
+      return right(unit);
+    } catch (e, st) {
+      appLogger.error('setPeerProxyEnabled failed', e, st);
+      return Left(e.toFailure());
+    }
   }
 
   @override
   Future<Either<Failure, bool>> isPeerProxyEnabled() async {
-    return right(false);
+    try {
+      final res = await _methodChannel.invokeMethod<bool>('isPeerProxyEnabled');
+      return right(res ?? false);
+    } catch (e, st) {
+      appLogger.error('isPeerProxyEnabled failed', e, st);
+      return Left(e.toFailure());
+    }
   }
 
   @override

macos/Runner/Handlers/MethodHandler.swift

@@ -245,6 +245,16 @@ class MethodHandler {
         let enabled = data?["enabled"] as? Bool ?? false
         self.setBlockAdsEnabled(result: result, enabled: enabled)
 
+      case "isPeerProxyEnabled":
+        Task {
+          await MainActor.run { result(MobileIsPeerShareEnabled()) }
+        }
+
+      case "setPeerProxyEnabled":
+        let data = call.arguments as? [String: Any]
+        let enabled = data?["enabled"] as? Bool ?? false
+        self.setPeerProxyEnabled(result: result, enabled: enabled)
+
       case "updateTelemetryEvents":
         guard let consent: Bool = self.decodeValue(from: call.arguments, result: result) else {
           return
@@ -1131,6 +1141,20 @@ class MethodHandler {
     }
   }
 
+  func setPeerProxyEnabled(result: @escaping FlutterResult, enabled: Bool) {
+    Task {
+      var error: NSError?
+      MobileSetPeerShareEnabled(enabled, &error)
+      if let error {
+        await self.handleFlutterError(error, result: result, code: "SET_PEER_PROXY_ERROR")
+        return
+      }
+      await MainActor.run {
+        result("ok")
+      }
+    }
+  }
+
   func updateTelemetryEvents(consent: Bool, result: @escaping FlutterResult) {
     Task {
       var error: NSError?