feat(announcements): bridge the cache to Dart and add the Announcements toggle

lib/features/settings/providers/announcements_provider.dart

@@ -0,0 +1,100 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import 'package:mostro/src/rust/api/announcements.dart' as announcements_api;
+
+/// The Announcements toggle (specs/006-announcement-channel §7).
+///
+/// Unlike its four neighbours, which are `shared_preferences` keys, this one
+/// lives in the Rust settings table: the value decides whether Rust opens a
+/// relay subscription, and the authority for that is on the side that opens
+/// it. Off means the subscription is closed at the tap, not that arriving
+/// notices are hidden.
+
+/// The Rust side of the toggle. Injected so screen tests never reach the
+/// bridge.
+class AnnouncementsBridge {
+  const AnnouncementsBridge();
+
+  Future<bool> enabled() => announcements_api.getAnnouncementsEnabled();
+
+  Future<void> setEnabled(bool enabled) =>
+      announcements_api.setAnnouncementsEnabled(enabled: enabled);
+}
+
+final announcementsBridgeProvider = Provider<AnnouncementsBridge>(
+  (ref) => const AnnouncementsBridge(),
+);
+
+class AnnouncementsEnabledNotifier extends StateNotifier<bool> {
+  AnnouncementsEnabledNotifier({required AnnouncementsBridge bridge})
+    : _bridge = bridge,
+      // On until Rust says otherwise: the persisted default (§7).
+      super(true) {
+    _load();
+  }
+
+  final AnnouncementsBridge _bridge;
+
+  /// Taps so far. A load that answers after one read the setting before its
+  /// write, so its value is older than the screen's; a failed write reloads
+  /// only when no newer tap has replaced it.
+  int _taps = 0;
+
+  /// Writes go one after another: two quick taps otherwise race to the
+  /// store, and the older one can land last.
+  Future<void> _writes = Future.value();
+
+  Future<void> _load() async {
+    try {
+      final enabled = await _bridge.enabled();
+      if (mounted && _taps == 0) state = enabled;
+    } catch (e) {
+      debugPrint('[announcements] reading the toggle failed: $e');
+    }
+  }
+
+  /// Applies the change to the UI first and persists after, so the toggle
+  /// answers the tap; a failed write is reported by returning false and the
+  /// toggle going back to what Rust holds.
+  Future<bool> set(bool value) {
+    final tap = ++_taps;
+    final before = state;
+    state = value;
+    final write = _writes.then((_) => _write(value, tap, before));
+    _writes = write.then((_) {});
+    return write;
+  }
+
+  Future<bool> _write(bool value, int tap, bool before) async {
+    try {
+      await _bridge.setEnabled(value);
+      return true;
+    } catch (e) {
+      debugPrint('[announcements] saving the toggle failed: $e');
+      if (mounted && tap == _taps) await _reload(tap, before);
+      return false;
+    }
+  }
+
+  /// After a refused write the screen shows a value Rust never took. What it
+  /// showed before the tap may be stale too — the load can still be in
+  /// flight — so Rust is asked again; a tap that lands meanwhile wins.
+  Future<void> _reload(int tap, bool before) async {
+    bool enabled;
+    try {
+      enabled = await _bridge.enabled();
+    } catch (e) {
+      debugPrint('[announcements] re-reading the toggle failed: $e');
+      enabled = before;
+    }
+    if (mounted && tap == _taps) state = enabled;
+  }
+}
+
+final announcementsEnabledProvider =
+    StateNotifierProvider<AnnouncementsEnabledNotifier, bool>(
+      (ref) => AnnouncementsEnabledNotifier(
+        bridge: ref.watch(announcementsBridgeProvider),
+      ),
+    );

lib/features/settings/screens/notification_settings_screen.dart

@@ -7,6 +7,7 @@ import 'package:mostro/core/app_routes.dart';
 import 'package:mostro/core/order_book_palette.dart';
 import 'package:mostro/core/settings_palette.dart';
 import 'package:mostro/features/settings/models/push_status_line.dart';
+import 'package:mostro/features/settings/providers/announcements_provider.dart';
 import 'package:mostro/features/settings/providers/notification_permission_provider.dart';
 import 'package:mostro/features/settings/providers/notification_prefs_provider.dart';
 import 'package:mostro/features/settings/providers/push_settings_provider.dart';
@@ -28,6 +29,12 @@ import 'package:mostro/shared/widgets/redesign_app_bar.dart';
 ///
 /// The event rows gate the in-app cards, not the push: a push carries no
 /// type to filter on (docs/PUSH_NOTIFICATIONS.md §9.1).
+///
+/// A third card holds the Announcements toggle (specs/006 §7): the project's
+/// signed notices, read from the relays. Off closes that subscription at the
+/// tap, which is why its value lives in Rust rather than in `shared_preferences`
+/// like the four rows above it — and why the OS permission does not gate it:
+/// an announcement posts no system notification.
 class NotificationSettingsScreen extends ConsumerWidget {
   const NotificationSettingsScreen({super.key});
 
@@ -125,6 +132,19 @@ class NotificationSettingsScreen extends ConsumerWidget {
             ),
           ),
           const SizedBox(height: settingsGroupGap),
+          Padding(
+            padding: const EdgeInsets.fromLTRB(2, 0, 2, 14),
+            child: Text(
+              l10n.announcementsGroupSubtitle,
+              style: TextStyle(
+                fontSize: 12,
+                height: 1.5,
+                color: book.textSecondary,
+              ),
+            ),
+          ),
+          const SettingsGroup(rows: [_AnnouncementsRow()]),
+          const SizedBox(height: settingsGroupGap),
           SettingsFootnote(
             icon: Icons.lock_outline,
             // Relevant in a privacy app: pushes travel through Google/Apple.
@@ -188,7 +208,7 @@ class _PushMasterRowState extends ConsumerState<_PushMasterRow> {
             value
                 ? Icons.notifications_active_outlined
                 : Icons.notifications_off_outlined,
-            size: 17,
+            size: 16,
             color: value ? book.limeIcon : book.textTertiary,
           ),
           const SizedBox(width: 12),
@@ -320,7 +340,7 @@ class _UnsupportedPlatformRow extends StatelessWidget {
         children: [
           Icon(
             Icons.notifications_off_outlined,
-            size: 17,
+            size: 16,
             color: book.textTertiary,
           ),
           const SizedBox(width: 12),
@@ -355,12 +375,99 @@ class _EventRow extends ConsumerWidget {
   final bool value;
   final bool enabled;
 
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final (title, description) = _copy(AppLocalizations.of(context), event);
+    return _ToggleRow(
+      icon: icon,
+      title: title,
+      description: description,
+      value: value,
+      onChanged: enabled ? (next) => _set(context, ref, next) : null,
+    );
+  }
+
+  Future<void> _set(BuildContext context, WidgetRef ref, bool next) async {
+    final ok = await ref
+        .read(notificationPrefsProvider.notifier)
+        .setEvent(event, next);
+    if (!ok && context.mounted) _saveFailed(context);
+  }
+
+  static (String, String) _copy(
+    AppLocalizations l10n,
+    NotificationEvent event,
+  ) => switch (event) {
+    NotificationEvent.tradeUpdates => (
+      l10n.notifTradeUpdatesTitle,
+      l10n.notifTradeUpdatesSubtitle,
+    ),
+    NotificationEvent.newMessages => (
+      l10n.notifNewMessagesTitle,
+      l10n.notifNewMessagesSubtitle,
+    ),
+    NotificationEvent.paymentAlerts => (
+      l10n.notifPaymentAlertsTitle,
+      l10n.notifPaymentAlertsSubtitle,
+    ),
+    NotificationEvent.disputeUpdates => (
+      l10n.notifDisputeUpdatesTitle,
+      l10n.notifDisputeUpdatesSubtitle,
+    ),
+  };
+}
+
+/// The Announcements toggle (specs/006 §7), persisted by Rust: off closes
+/// the relay subscription at the tap. Never gated by the OS permission.
+class _AnnouncementsRow extends ConsumerWidget {
+  const _AnnouncementsRow();
+
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final l10n = AppLocalizations.of(context);
-    final book = OrderBookPalette.of(context);
-    final (title, description) = _copy(l10n, event);
+    return _ToggleRow(
+      icon: Icons.campaign_outlined,
+      title: l10n.notifAnnouncementsTitle,
+      description: l10n.notifAnnouncementsSubtitle,
+      value: ref.watch(announcementsEnabledProvider),
+      onChanged: (next) => _set(context, ref, next),
+    );
+  }
 
+  Future<void> _set(BuildContext context, WidgetRef ref, bool next) async {
+    final ok = await ref.read(announcementsEnabledProvider.notifier).set(next);
+    if (!ok && context.mounted) _saveFailed(context);
+  }
+}
+
+void _saveFailed(BuildContext context) {
+  ScaffoldMessenger.of(context).showSnackBar(
+    SnackBar(
+      content: Text(AppLocalizations.of(context).notificationPrefSaveFailed),
+    ),
+  );
+}
+
+/// One row of a settings group: a glyph, a 13/600 title over an 11/400
+/// description, and a toggle. [onChanged] null disables the toggle.
+class _ToggleRow extends StatelessWidget {
+  const _ToggleRow({
+    required this.icon,
+    required this.title,
+    required this.description,
+    required this.value,
+    required this.onChanged,
+  });
+
+  final IconData icon;
+  final String title;
+  final String description;
+  final bool value;
+  final ValueChanged<bool>? onChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    final book = OrderBookPalette.of(context);
     return Padding(
       padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 14),
       child: Row(
@@ -370,7 +477,7 @@ class _EventRow extends ConsumerWidget {
         children: [
           Icon(
             icon,
-            size: 17,
+            size: 16,
             color: value ? book.limeIcon : book.textTertiary,
           ),
           const SizedBox(width: 12),
@@ -402,49 +509,12 @@ class _EventRow extends ConsumerWidget {
           MostroToggle(
             value: value,
             semanticLabel: title,
-            onChanged: enabled ? (next) => _set(context, ref, next) : null,
+            onChanged: onChanged,
           ),
         ],
       ),
     );
   }
-
-  Future<void> _set(BuildContext context, WidgetRef ref, bool next) async {
-    final ok = await ref
-        .read(notificationPrefsProvider.notifier)
-        .setEvent(event, next);
-    if (!ok && context.mounted) {
-      ScaffoldMessenger.of(context).showSnackBar(
-        SnackBar(
-          content: Text(
-            AppLocalizations.of(context).notificationPrefSaveFailed,
-          ),
-        ),
-      );
-    }
-  }
-
-  static (String, String) _copy(
-    AppLocalizations l10n,
-    NotificationEvent event,
-  ) => switch (event) {
-    NotificationEvent.tradeUpdates => (
-      l10n.notifTradeUpdatesTitle,
-      l10n.notifTradeUpdatesSubtitle,
-    ),
-    NotificationEvent.newMessages => (
-      l10n.notifNewMessagesTitle,
-      l10n.notifNewMessagesSubtitle,
-    ),
-    NotificationEvent.paymentAlerts => (
-      l10n.notifPaymentAlertsTitle,
-      l10n.notifPaymentAlertsSubtitle,
-    ),
-    NotificationEvent.disputeUpdates => (
-      l10n.notifDisputeUpdatesTitle,
-      l10n.notifDisputeUpdatesSubtitle,
-    ),
-  };
 }
 
 // ── Permission banners ────────────────────────────────────────────────────────

lib/l10n/app_de.arb

@@ -394,6 +394,9 @@
   "notifPaymentAlertsSubtitle": "Bestätigungen und Fehler von Lightning-Zahlungen",
   "notifDisputeUpdatesTitle": "Streitfall-Updates",
   "notifDisputeUpdatesSubtitle": "Schlichter-Aktionen und Streitbeilegungen",
+  "notifAnnouncementsTitle": "Ankündigungen",
+  "notifAnnouncementsSubtitle": "Versionen, Ausfälle und Relay-Änderungen, signiert vom Mostro-Projekt",
+  "announcementsGroupSubtitle": "Ankündigungen werden von den Relays gelesen und nie beantwortet: Nichts über dich wird gesendet.",
   "searchCurrenciesHint": "Währungen suchen…",
   "noCurrenciesFoundMessage": "Keine Währungen gefunden",
   "shareLogsTooltip": "Protokolle teilen",

lib/l10n/app_en.arb

@@ -1714,6 +1714,18 @@
   "@notifDisputeUpdatesSubtitle": {
     "description": "Subtitle of the dispute updates notification toggle"
   },
+  "notifAnnouncementsTitle": "Announcements",
+  "@notifAnnouncementsTitle": {
+    "description": "Title of the Announcements toggle in notification settings (specs/006)"
+  },
+  "notifAnnouncementsSubtitle": "Releases, outages and relay changes, signed by the Mostro project",
+  "@notifAnnouncementsSubtitle": {
+    "description": "Subtitle of the Announcements toggle"
+  },
+  "announcementsGroupSubtitle": "Announcements are read from the relays and never answered: nothing about you is sent.",
+  "@announcementsGroupSubtitle": {
+    "description": "Line above the Announcements toggle: the channel is one-way, nothing is reported back"
+  },
   "searchCurrenciesHint": "Search currencies…",
   "@searchCurrenciesHint": {
     "description": "Hint text of the currency search field"

lib/l10n/app_es.arb

@@ -394,6 +394,9 @@
   "notifPaymentAlertsSubtitle": "Confirmaciones y fallos de pagos Lightning",
   "notifDisputeUpdatesTitle": "Actualizaciones de disputas",
   "notifDisputeUpdatesSubtitle": "Acciones de los resolutores y resoluciones de disputas",
+  "notifAnnouncementsTitle": "Anuncios",
+  "notifAnnouncementsSubtitle": "Versiones, caídas y cambios de relays, firmados por el proyecto Mostro",
+  "announcementsGroupSubtitle": "Los anuncios se leen de los relays y nunca se responden: no se envía nada sobre ti.",
   "searchCurrenciesHint": "Buscar monedas…",
   "noCurrenciesFoundMessage": "No se encontraron monedas",
   "shareLogsTooltip": "Compartir registros",

lib/l10n/app_fr.arb

@@ -394,6 +394,9 @@
   "notifPaymentAlertsSubtitle": "Confirmations et échecs de paiements Lightning",
   "notifDisputeUpdatesTitle": "Mises à jour des litiges",
   "notifDisputeUpdatesSubtitle": "Actions des médiateurs et résolutions de litiges",
+  "notifAnnouncementsTitle": "Annonces",
+  "notifAnnouncementsSubtitle": "Versions, pannes et changements de relais, signés par le projet Mostro",
+  "announcementsGroupSubtitle": "Les annonces sont lues depuis les relais et jamais répondues : rien vous concernant n'est envoyé.",
   "searchCurrenciesHint": "Rechercher des devises…",
   "noCurrenciesFoundMessage": "Aucune devise trouvée",
   "shareLogsTooltip": "Partager les journaux",

lib/l10n/app_it.arb

@@ -394,6 +394,9 @@
   "notifPaymentAlertsSubtitle": "Conferme ed errori dei pagamenti Lightning",
   "notifDisputeUpdatesTitle": "Aggiornamenti dispute",
   "notifDisputeUpdatesSubtitle": "Azioni dei mediatori e risoluzioni delle dispute",
+  "notifAnnouncementsTitle": "Annunci",
+  "notifAnnouncementsSubtitle": "Versioni, interruzioni e cambi di relay, firmati dal progetto Mostro",
+  "announcementsGroupSubtitle": "Gli annunci vengono letti dai relay e mai risposti: non viene inviato nulla su di te.",
   "searchCurrenciesHint": "Cerca valute…",
   "noCurrenciesFoundMessage": "Nessuna valuta trovata",
   "shareLogsTooltip": "Condividi i log",