feat(app): connect to server before wallet open, status in bottom bar

- ConnectAndSync() no longer bails early when no wallet is open:
  connection is established immediately after the wizard completes
  (Electrum-style), sync starts only once an account is available
- KeepAlive tick no longer requires IsWalletOpen so the connection is
  maintained and auto-reconnected at all times
- WalletSynchronizer is lazily created on first sync (not on connect)
  to avoid a null-ref guard on _synchronizer
- Connection status indicator (dot + text) moved from wallet header to
  the status bar (always visible); tapping it still opens the server
  settings overlay
- Menu "Rete" removed: Discover and ResetCerts are inside the server
  settings overlay; redundant top-level menu entry eliminated
- "Server" button in settings overlay is no longer gated on IsWalletOpen

src/App/ViewModels/MainWindowViewModel.cs

@@ -397,7 +397,9 @@ public partial class MainWindowViewModel : ViewModelBase
 
     private async Task KeepAliveTickAsync()
     {
-        if (!IsWalletOpen || IsSyncing)
+        // Vale anche senza wallet aperto: se l'utente si è connesso dalle
+        // impostazioni server, la connessione va mantenuta e riconnessa.
+        if (IsSyncing)
             return;
         if (_client is { IsConnected: true })
         {
@@ -461,6 +463,9 @@ public partial class MainWindowViewModel : ViewModelBase
             ? Loc.Tr("msg.welcome.existing")
             : Loc.Tr("msg.welcome.new");
         RefreshServers();
+        // Come Electrum: ci si connette al server già durante il setup, senza
+        // aspettare l'apertura di un wallet (la sync parte poi all'apertura).
+        _ = ConnectAndSync();
     }
 
     private void RefreshServers()
@@ -776,8 +781,6 @@ public partial class MainWindowViewModel : ViewModelBase
     [RelayCommand]
     private async Task ConnectAndSync()
     {
-        if (_account is null || _doc is null)
-            return;
         if (IsSyncing)
         {
             _resyncRequested = true;
@@ -812,8 +815,18 @@ public partial class MainWindowViewModel : ViewModelBase
                 IsConnected = true;
                 _autoReconnect = true;
                 ConnectionStatus = $"{Loc.Tr("conn.connectedto")} {host}:{port}{(UseSsl ? " (TLS)" : "")}";
-                // Synchronizer per connessione: conserva la cache di tx e
-                // prove verificate, così le risincronizzazioni sono incrementali.
+            }
+
+            // Senza un wallet aperto ci si limita a stabilire/verificare la
+            // connessione: la sincronizzazione richiede un account.
+            if (_account is null || _doc is null)
+                return;
+
+            // Synchronizer legato all'account corrente, creato alla prima sync
+            // dopo la connessione: conserva la cache di tx e prove verificate,
+            // così le risincronizzazioni sono incrementali.
+            if (_synchronizer is null)
+            {
                 _synchronizer = new WalletSynchronizer(_account, _client, _doc.GapLimit);
                 _synchronizer.Progress += msg => Dispatcher.UIThread.Post(() => StatusMessage = msg);
             }
@@ -823,7 +836,7 @@ public partial class MainWindowViewModel : ViewModelBase
             do
             {
                 _resyncRequested = false;
-                var result = await _synchronizer!.SyncOnceAsync();
+                var result = await _synchronizer.SyncOnceAsync();
                 _lastTransactions = result.Transactions;
 
                 _doc.Cache = new SyncCache

src/App/Views/MainWindow.axaml

@@ -26,10 +26,6 @@
                 <MenuItem Header="{Binding Loc[menu.file.close]}" Command="{Binding CloseWalletCommand}"
                           IsEnabled="{Binding IsWalletOpen}"/>
             </MenuItem>
-            <MenuItem Header="{Binding Loc[menu.net]}">
-                <MenuItem Header="{Binding Loc[menu.net.discover]}" Command="{Binding DiscoverServersCommand}"/>
-                <MenuItem Header="{Binding Loc[menu.net.resetcerts]}" Command="{Binding ResetCertificatesCommand}"/>
-            </MenuItem>
             <MenuItem Header="{Binding Loc[menu.settings]}"
                       Command="{Binding OpenSettingsCommand}"/>
         </Menu>
@@ -159,29 +155,13 @@
         <!-- ============ PANNELLO WALLET ============ -->
         <Grid Grid.Row="1" RowDefinitions="Auto,*" IsVisible="{Binding IsWalletOpen}" Margin="16">
 
-            <!-- Testata: saldo + rete · stato connessione.
-                 Connetti/sincronizza è automatico; chiudi wallet è in File.
-                 Le impostazioni del server sono in Impostazioni → Server. -->
-            <Grid Grid.Row="0" ColumnDefinitions="*,Auto" Margin="0,0,0,12">
-                <StackPanel Grid.Column="0" Spacing="2">
+            <!-- Testata: saldo + rete. Connetti/sincronizza è automatico; chiudi
+                 wallet è in File. Lo stato connessione è nella barra in basso. -->
+            <StackPanel Grid.Row="0" Spacing="2" Margin="0,0,0,12">
                 <TextBlock Text="{Binding BalanceText}" FontSize="30" FontWeight="Bold"/>
                 <TextBlock Text="{Binding UnconfirmedText}" Foreground="Orange"/>
                 <TextBlock Text="{Binding NetworkInfo}" FontSize="12" Foreground="Gray"/>
             </StackPanel>
-                <!-- Cliccabile: apre le impostazioni del server -->
-                <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="6"
-                            VerticalAlignment="Top" Cursor="Hand" Background="Transparent"
-                            ToolTip.Tip="{Binding Loc[server.title]}"
-                            Tapped="OnConnectionStatusTapped">
-                    <Ellipse Width="10" Height="10" Fill="LimeGreen" VerticalAlignment="Center"
-                             IsVisible="{Binding IsConnected}"/>
-                    <Ellipse Width="10" Height="10" Fill="IndianRed" VerticalAlignment="Center"
-                             IsVisible="{Binding !IsConnected}"/>
-                    <TextBlock Text="{Binding ConnectionStatus}"
-                               Foreground="{DynamicResource SystemAccentColor}"
-                               VerticalAlignment="Center"/>
-                </StackPanel>
-            </Grid>
 
             <!-- Tab: Storico / Invia / Ricevi / Indirizzi / Contatti -->
             <TabControl Grid.Row="1">
@@ -331,10 +311,27 @@
             </TabControl>
         </Grid>
 
-        <!-- Barra di stato -->
+        <!-- Barra di stato: messaggio a sinistra, stato connessione a destra.
+             Lo stato connessione è cliccabile e apre le impostazioni del server. -->
         <Border Grid.Row="2" Background="{DynamicResource SystemControlBackgroundChromeMediumBrush}"
                 Padding="10,6">
-            <TextBlock Text="{Binding StatusMessage}" FontSize="12" TextWrapping="Wrap"/>
+            <Grid ColumnDefinitions="*,Auto">
+                <TextBlock Grid.Column="0" Text="{Binding StatusMessage}" FontSize="12"
+                           TextWrapping="Wrap" VerticalAlignment="Center"/>
+                <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="6"
+                            Margin="12,0,0,0" VerticalAlignment="Center"
+                            Cursor="Hand" Background="Transparent"
+                            ToolTip.Tip="{Binding Loc[server.title]}"
+                            Tapped="OnConnectionStatusTapped">
+                    <Ellipse Width="10" Height="10" Fill="LimeGreen" VerticalAlignment="Center"
+                             IsVisible="{Binding IsConnected}"/>
+                    <Ellipse Width="10" Height="10" Fill="IndianRed" VerticalAlignment="Center"
+                             IsVisible="{Binding !IsConnected}"/>
+                    <TextBlock Text="{Binding ConnectionStatus}" FontSize="12"
+                               Foreground="{DynamicResource SystemAccentColor}"
+                               VerticalAlignment="Center"/>
+                </StackPanel>
+            </Grid>
         </Border>
 
         <!-- ============ OVERLAY DETTAGLIO INDIRIZZO ============ -->
@@ -540,11 +537,10 @@
                         </WrapPanel>
                     </StackPanel>
 
-                    <!-- Server di indicizzazione -->
+                    <!-- Server di indicizzazione (configurabile anche prima di aprire un wallet) -->
                     <Button Content="{Binding Loc[settings.server]}"
                             HorizontalAlignment="Left"
-                            Command="{Binding OpenServerSettingsCommand}"
-                            IsEnabled="{Binding IsWalletOpen}"/>
+                            Command="{Binding OpenServerSettingsCommand}"/>
 
                     <Button Content="{Binding Loc[addr.close]}"
                             HorizontalAlignment="Right"