feat(nwc): implement real NIP-47 Nostr Wallet Connect client

lib/features/settings/providers/nwc_provider.dart

@@ -1,8 +1,12 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
 // Sentinel for copyWith nullable fields.
 const _unset = Object();
 
+/// SharedPreferences key for the persisted NWC URI.
+const kNwcUriKey = 'settings.nwcUri';
+
 /// Wallet connection state held in memory.
 ///
 /// `null`  → no wallet connected.
@@ -40,13 +44,24 @@ class NwcWalletState {
 // ── Notifier ───────────────────────────────────────────────────────────────────
 
 class NwcNotifier extends StateNotifier<NwcWalletState?> {
-  NwcNotifier() : super(null);
+  NwcNotifier({SharedPreferences? prefs}) : _prefs = prefs, super(null);
+
+  final SharedPreferences? _prefs;
 
   /// Store wallet state after a successful `connect_wallet` call.
-  void setConnected(NwcWalletState wallet) => state = wallet;
+  /// Persists the NWC URI so it survives app restarts.
+  void setConnected(NwcWalletState wallet, {String? nwcUri}) {
+    state = wallet;
+    if (nwcUri != null) {
+      _prefs?.setString(kNwcUriKey, nwcUri);
+    }
+  }
 
   /// Clear wallet state after `disconnect_wallet`.
-  void setDisconnected() => state = null;
+  void setDisconnected() {
+    state = null;
+    _prefs?.remove(kNwcUriKey);
+  }
 
   /// Update balance from a `get_balance` result.
   void updateBalance(int? sats) {
@@ -59,6 +74,7 @@ class NwcNotifier extends StateNotifier<NwcWalletState?> {
 // ── Providers ─────────────────────────────────────────────────────────────────
 
 /// Wallet connection state. `null` when no wallet is connected.
+/// Override in `main()` via [ProviderScope] to inject [SharedPreferences].
 final nwcProvider =
     StateNotifierProvider<NwcNotifier, NwcWalletState?>((ref) => NwcNotifier());
 

lib/features/settings/screens/connect_wallet_screen.dart

@@ -60,6 +60,7 @@ class _ConnectWalletScreenState extends ConsumerState<ConnectWalletScreen> {
               walletName: info.walletName,
               balanceSats: info.balanceSats?.toInt(),
             ),
+            nwcUri: _uriController.text.trim(),
           );
       context.go(AppRoute.walletSettings);
     } catch (e) {

lib/features/settings/screens/settings_screen.dart

@@ -33,6 +33,11 @@ class _SettingsScreenState extends ConsumerState<SettingsScreen> {
     return Scaffold(
       appBar: AppBar(
         title: Text(AppLocalizations.of(context).settingsScreenTitle),
+        leading: IconButton(
+          icon: const Icon(Icons.arrow_back),
+          onPressed: () =>
+              context.canPop() ? context.pop() : context.go(AppRoute.home),
+        ),
       ),
       body: ListView(
         padding: const EdgeInsets.all(AppSpacing.lg),

lib/features/settings/screens/wallet_settings_screen.dart

@@ -23,7 +23,14 @@ class WalletSettingsScreen extends ConsumerWidget {
     final cardBg = colors?.backgroundCard ?? const Color(0xFF1E2230);
 
     return Scaffold(
-      appBar: AppBar(title: const Text('Wallet Configuration')),
+      appBar: AppBar(
+        title: const Text('Wallet Configuration'),
+        leading: IconButton(
+          icon: const Icon(Icons.arrow_back),
+          onPressed: () =>
+              context.canPop() ? context.pop() : context.go(AppRoute.settings),
+        ),
+      ),
       body: Padding(
         padding: const EdgeInsets.all(AppSpacing.lg),
         child: wallet == null

lib/main.dart

@@ -11,6 +11,8 @@ import 'package:mostro/features/walkthrough/providers/first_run_provider.dart';
 import 'package:mostro/features/account/providers/backup_reminder_provider.dart';
 import 'package:mostro/src/rust/frb_generated.dart';
 import 'package:mostro/src/rust/api.dart' as rust_api;
+import 'package:mostro/features/settings/providers/nwc_provider.dart';
+import 'package:mostro/src/rust/api/nwc.dart' as nwc_api;
 import 'package:mostro/src/rust/api/nostr.dart' as nostr_api;
 import 'package:mostro/src/rust/api/orders.dart' as orders_api;
 
@@ -58,7 +60,7 @@ Future<void> main() async {
   // Watch for connection state changes in background (logs appear in flutter output).
   _watchConnectionState();
 
-  runApp(ProviderScope(
+  final container = ProviderContainer(
     overrides: [
       firstRunProvider.overrideWith(
         (ref) => FirstRunNotifier(initialValue: firstRunComplete),
@@ -69,11 +71,44 @@ Future<void> main() async {
       settingsProvider.overrideWith(
         (ref) => SettingsNotifier(prefs: prefs, initial: savedSettings),
       ),
+      nwcProvider.overrideWith(
+        (ref) => NwcNotifier(prefs: prefs),
+      ),
     ],
+  );
+
+  // Restore NWC wallet connection if a URI was saved from a previous session.
+  final savedNwcUri = prefs.getString(kNwcUriKey);
+  if (savedNwcUri != null) {
+    _restoreNwcConnection(savedNwcUri, container);
+  }
+
+  runApp(UncontrolledProviderScope(
+    container: container,
     child: const MostroApp(),
   ));
 }
 
+/// Reconnect a previously saved NWC wallet in the background.
+void _restoreNwcConnection(String nwcUri, ProviderContainer container) {
+  Future.microtask(() async {
+    try {
+      final info = await nwc_api.connectWallet(nwcUri: nwcUri);
+      container.read(nwcProvider.notifier).setConnected(
+            NwcWalletState(
+              walletPubkey: info.walletPubkey,
+              relayUrls: info.relayUrls,
+              walletName: info.walletName,
+              balanceSats: info.balanceSats?.toInt(),
+            ),
+          );
+      debugPrint('[nwc] wallet restored: ${info.walletName ?? info.walletPubkey}');
+    } catch (e) {
+      debugPrint('[nwc] wallet restore failed: $e');
+    }
+  });
+}
+
 /// Guards against overlapping diagnostic order polls on rapid reconnects.
 bool _isPollingOrders = false;
 

rust/Cargo.toml

@@ -10,7 +10,7 @@ crate-type = ["cdylib", "staticlib"]
 flutter_rust_bridge = "=2.11.1"
 
 # Nostr & Mostro protocol
-nostr-sdk = { version = "0.44", default-features = false, features = ["nip44", "nip59"] }
+nostr-sdk = { version = "0.44", default-features = false, features = ["nip44", "nip47", "nip59"] }
 mostro-core = "0.8.0"
 
 # Serialization