global desktop mode feature

apps/weblibre/lib/features/geckoview/domain/providers/desktop_mode.dart

@@ -19,6 +19,7 @@
  */
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 import 'package:weblibre/features/geckoview/domain/providers/tab_session.dart';
+import 'package:weblibre/features/user/domain/repositories/general_settings.dart';
 
 part 'desktop_mode.g.dart';
 
@@ -43,6 +44,11 @@ class DesktopMode extends _$DesktopMode {
       }
     });
 
-    return false;
+    // Seed the initial value from the browser-wide default so a newly opened
+    // tab's menu checkbox matches the desktop mode it was actually created with
+    // natively (GeckoTabsApi seeds new tabs from BrowserState.desktopMode).
+    // Read (not watch) so toggling the global default never clobbers an
+    // existing tab's per-tab override.
+    return ref.read(generalSettingsWithDefaultsProvider).globalDesktopMode;
   }
 }

apps/weblibre/lib/features/geckoview/domain/providers/desktop_mode.g.dart

@@ -57,7 +57,7 @@ final class DesktopModeProvider extends $NotifierProvider<DesktopMode, bool> {
   }
 }
 
-String _$desktopModeHash() => r'18550009e95a23ff82d30206ce81daa859c57c26';
+String _$desktopModeHash() => r'727c8a884de5c21499f4b3ae6835af1115f649f2';
 
 final class DesktopModeFamily extends $Family
     with $ClassFamilyOverride<DesktopMode, bool, bool, bool, String> {

apps/weblibre/lib/features/geckoview/features/browser/domain/services/engine_settings_replication.dart

@@ -25,6 +25,7 @@ import 'package:flutter_mozilla_components/flutter_mozilla_components.dart';
 import 'package:riverpod/riverpod.dart';
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 import 'package:weblibre/core/logger.dart';
+import 'package:weblibre/features/geckoview/domain/providers/desktop_mode.dart';
 import 'package:weblibre/features/geckoview/features/browser/domain/services/browser_addon.dart';
 import 'package:weblibre/features/geckoview/features/preferences/data/repositories/preference_observer.dart';
 import 'package:weblibre/features/geckoview/features/preferences/data/repositories/preference_settings.dart';
@@ -158,6 +159,37 @@ class EngineSettingsReplicationService
       },
     );
 
+    ref.listen(
+      fireImmediately: true,
+      generalSettingsWithDefaultsProvider.select(
+        (settings) => settings.globalDesktopMode,
+      ),
+      (previous, next) async {
+        // Only an actual toggle (not the initial startup fire) should rewrite
+        // existing tabs; the initial fire just sets the default for new tabs.
+        final isUserToggle = previous != null;
+
+        await _service.setGlobalDesktopMode(
+          next,
+          applyToExistingTabs: isUserToggle,
+        );
+
+        if (isUserToggle) {
+          // The native side applied the new value to all existing tabs.
+          // Invalidate the per-tab desktop-mode notifiers so their menu
+          // checkboxes re-seed and reflect it.
+          ref.invalidate(desktopModeProvider);
+        }
+      },
+      onError: (error, stackTrace) {
+        logger.e(
+          'Error listening to globalDesktopMode',
+          error: error,
+          stackTrace: stackTrace,
+        );
+      },
+    );
+
     ref.listen(
       fireImmediately: true,
       engineSettingsRepositoryProvider,

apps/weblibre/lib/features/geckoview/features/browser/domain/services/engine_settings_replication.g.dart

@@ -44,7 +44,7 @@ final class EngineSettingsReplicationServiceProvider
 }
 
 String _$engineSettingsReplicationServiceHash() =>
-    r'8f37476c9beecd6cc70a07b8cd3a51864b077176';
+    r'36f43a382419203ec53cac71fe51b1d30df2a0c6';
 
 abstract class _$EngineSettingsReplicationService extends $Notifier<void> {
   void build();

apps/weblibre/lib/features/geckoview/features/preferences/data/models/preference_setting.dart

@@ -64,6 +64,15 @@ class PreferenceSetting with FastEquatable {
   final String? description;
 
   final bool requireUserOptIn;
+
+  /// Marks this preference as an enforced hardening policy: it renders as a
+  /// locked, non-interactive row and cannot be toggled off in the UI.
+  ///
+  /// This is a *policy* flag, not a claim that [value] equals Gecko's default.
+  /// Many locked preferences intentionally deviate from the engine default
+  /// (e.g. blanking the telemetry/crash-report/OHTTP endpoints), so auditing
+  /// locked values against Gecko defaults is expected to show differences —
+  /// those are deliberate overrides, not bugs.
   final bool locked;
   final bool enforceOnStartup;