feat(app): Avalonia UI shell

src/App/App.axaml

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+<Application xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             x:Class="PalladiumWallet.App.App"
+             xmlns:local="using:PalladiumWallet.App"
+             RequestedThemeVariant="Default">
+             <!-- "Default" ThemeVariant follows system theme variant. "Dark" or "Light" are other available options. -->
+
+    <Application.DataTemplates>
+        <local:ViewLocator/>
+    </Application.DataTemplates>
+  
+    <Application.Styles>
+        <FluentTheme />
+    </Application.Styles>
+</Application>

src/App/App.axaml.cs

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+using Avalonia;
+using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Data.Core;
+using Avalonia.Data.Core.Plugins;
+using System.Linq;
+using Avalonia.Markup.Xaml;
+using PalladiumWallet.App.ViewModels;
+using PalladiumWallet.App.Views;
+
+namespace PalladiumWallet.App;
+
+public partial class App : Application
+{
+    public override void Initialize()
+    {
+        AvaloniaXamlLoader.Load(this);
+    }
+
+    public override void OnFrameworkInitializationCompleted()
+    {
+        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
+        {
+            desktop.MainWindow = new MainWindow
+            {
+                DataContext = new MainWindowViewModel(),
+            };
+        }
+
+        base.OnFrameworkInitializationCompleted();
+    }
+}

src/App/Program.cs

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+using Avalonia;
+using System;
+
+namespace PalladiumWallet.App;
+
+sealed class Program
+{
+    // Initialization code. Don't use any Avalonia, third-party APIs or any
+    // SynchronizationContext-reliant code before AppMain is called: things aren't initialized
+    // yet and stuff might break.
+    [STAThread]
+    public static void Main(string[] args) => BuildAvaloniaApp()
+        .StartWithClassicDesktopLifetime(args);
+
+    // Avalonia configuration, don't remove; also used by visual designer.
+    public static AppBuilder BuildAvaloniaApp()
+        => AppBuilder.Configure<App>()
+            .UsePlatformDetect()
+#if DEBUG
+            .WithDeveloperTools()
+#endif
+            .WithInterFont()
+            .LogToTrace();
+}

src/App/ViewLocator.cs

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+using System;
+using System.Diagnostics.CodeAnalysis;
+using Avalonia.Controls;
+using Avalonia.Controls.Templates;
+using PalladiumWallet.App.ViewModels;
+
+namespace PalladiumWallet.App;
+
+/// <summary>
+/// Given a view model, returns the corresponding view if possible.
+/// </summary>
+[RequiresUnreferencedCode(
+    "Default implementation of ViewLocator involves reflection which may be trimmed away.",
+    Url = "https://docs.avaloniaui.net/docs/concepts/view-locator")]
+public class ViewLocator : IDataTemplate
+{
+    public Control? Build(object? param)
+    {
+        if (param is null)
+            return null;
+        
+        var name = param.GetType().FullName!.Replace("ViewModel", "View", StringComparison.Ordinal);
+        var type = Type.GetType(name);
+
+        if (type != null)
+        {
+            return (Control)Activator.CreateInstance(type)!;
+        }
+        
+        return new TextBlock { Text = "Not Found: " + name };
+    }
+
+    public bool Match(object? data)
+    {
+        return data is ViewModelBase;
+    }
+}

src/App/ViewModels/MainWindowViewModel.cs

@@ -0,0 +1,396 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Threading.Tasks;
+using Avalonia.Threading;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using NBitcoin;
+using PalladiumWallet.Core.Chain;
+using PalladiumWallet.Core.Crypto;
+using PalladiumWallet.Core.Net;
+using PalladiumWallet.Core.Spv;
+using PalladiumWallet.Core.Storage;
+using PalladiumWallet.Core.Wallet;
+
+namespace PalladiumWallet.App.ViewModels;
+
+/// <summary>Riga dello storico transazioni per la vista.</summary>
+public sealed record HistoryRow(string Conferma, string Importo, string Txid, string Verificata);
+
+/// <summary>
+/// ViewModel unico dell'applicazione (wizard §15 ridotto + dashboard):
+/// pannello di setup (crea/ripristina/apri) e pannello wallet
+/// (saldo, ricevi, storico, invia, server).
+/// </summary>
+public partial class MainWindowViewModel : ViewModelBase
+{
+    private WalletDocument? _doc;
+    private HdAccount? _account;
+    private string? _walletPath;
+    private string? _password;
+    private ElectrumClient? _client;
+    private IReadOnlyDictionary<string, Transaction>? _lastTransactions;
+    private BuiltTransaction? _pendingSend;
+
+    // ---- selezione rete e stato pannelli ----
+
+    public string[] Networks { get; } = ["mainnet", "testnet", "regtest"];
+
+    [ObservableProperty]
+    private string selectedNetwork = "mainnet";
+
+    [ObservableProperty]
+    [NotifyPropertyChangedFor(nameof(IsSetupVisible))]
+    private bool isWalletOpen;
+
+    public bool IsSetupVisible => !IsWalletOpen;
+
+    [ObservableProperty]
+    private bool walletFileExists;
+
+    [ObservableProperty]
+    private string statusMessage = "";
+
+    // ---- pannello setup ----
+
+    [ObservableProperty]
+    private string mnemonicInput = "";
+
+    [ObservableProperty]
+    private string passphraseInput = "";
+
+    [ObservableProperty]
+    private string passwordInput = "";
+
+    // ---- pannello wallet ----
+
+    [ObservableProperty]
+    private string balanceText = "—";
+
+    [ObservableProperty]
+    private string unconfirmedText = "";
+
+    [ObservableProperty]
+    private string networkInfo = "";
+
+    [ObservableProperty]
+    private string receiveAddress = "";
+
+    [ObservableProperty]
+    private string serverInput = "";
+
+    [ObservableProperty]
+    private bool useSsl;
+
+    [ObservableProperty]
+    private string connectionStatus = "non connesso";
+
+    [ObservableProperty]
+    private bool isSyncing;
+
+    public ObservableCollection<HistoryRow> History { get; } = [];
+
+    // ---- pannello invia ----
+
+    [ObservableProperty]
+    private string sendTo = "";
+
+    [ObservableProperty]
+    private string sendAmount = "";
+
+    [ObservableProperty]
+    private string sendFeeRate = "1";
+
+    [ObservableProperty]
+    private bool sendAll;
+
+    [ObservableProperty]
+    private string sendPreview = "";
+
+    [ObservableProperty]
+    private bool hasPendingSend;
+
+    public MainWindowViewModel()
+    {
+        RefreshSetupState();
+    }
+
+    private NetKind Net => Enum.Parse<NetKind>(SelectedNetwork, ignoreCase: true);
+    private ChainProfile Profile => ChainProfiles.For(Net);
+
+    partial void OnSelectedNetworkChanged(string value) => RefreshSetupState();
+
+    private void RefreshSetupState()
+    {
+        WalletFileExists = WalletStore.Exists(AppPaths.DefaultWalletPath(Net));
+        StatusMessage = WalletFileExists
+            ? "Trovato un wallet esistente: inserisci la password (se impostata) e apri."
+            : "Nessun wallet su questa rete: creane uno nuovo o ripristina da seed.";
+        ServerInput = $"127.0.0.1:{Profile.DefaultTcpPort}";
+    }
+
+    // ---------- comandi setup ----------
+
+    [RelayCommand]
+    private void GenerateMnemonic()
+    {
+        MnemonicInput = Bip39.Generate(MnemonicLength.Twelve).ToString();
+        StatusMessage = "Nuova mnemonica generata: SCRIVILA SU CARTA prima di continuare.";
+    }
+
+    [RelayCommand]
+    private void CreateOrRestore()
+    {
+        try
+        {
+            var (doc, account) = WalletLoader.NewFromMnemonic(
+                MnemonicInput,
+                string.IsNullOrEmpty(PassphraseInput) ? null : PassphraseInput,
+                ScriptKind.NativeSegwit,
+                Profile);
+            var path = AppPaths.DefaultWalletPath(Net);
+            var password = string.IsNullOrEmpty(PasswordInput) ? null : PasswordInput;
+            WalletStore.Save(doc, path, password);
+            OpenLoaded(doc, account, path, password);
+        }
+        catch (Exception ex)
+        {
+            StatusMessage = $"Errore: {ex.Message}";
+        }
+    }
+
+    [RelayCommand]
+    private void OpenExisting()
+    {
+        try
+        {
+            var path = AppPaths.DefaultWalletPath(Net);
+            var password = string.IsNullOrEmpty(PasswordInput) ? null : PasswordInput;
+            var doc = WalletStore.Load(path, password);
+            OpenLoaded(doc, WalletLoader.ToAccount(doc), path, password);
+        }
+        catch (WrongPasswordException)
+        {
+            StatusMessage = "Password errata.";
+        }
+        catch (Exception ex)
+        {
+            StatusMessage = $"Errore: {ex.Message}";
+        }
+    }
+
+    private void OpenLoaded(WalletDocument doc, HdAccount account, string path, string? password)
+    {
+        _doc = doc;
+        _account = account;
+        _walletPath = path;
+        _password = password;
+        MnemonicInput = PassphraseInput = PasswordInput = "";
+
+        NetworkInfo = $"{doc.Network} · {doc.ScriptKind} · m/{doc.AccountPath}"
+            + (doc.IsWatchOnly ? " · watch-only" : "");
+        ApplyCache(doc.Cache);
+        IsWalletOpen = true;
+        StatusMessage = doc.Cache is null
+            ? "Wallet aperto. Connettiti a un server per sincronizzare."
+            : "Wallet aperto (dati dell'ultima sincronizzazione).";
+    }
+
+    private void ApplyCache(SyncCache? cache)
+    {
+        if (_account is null)
+            return;
+        if (cache is null)
+        {
+            BalanceText = $"0.00000000 {Profile.CoinUnit}";
+            UnconfirmedText = "";
+            ReceiveAddress = _account.GetReceiveAddress(0).ToString();
+            History.Clear();
+            return;
+        }
+        BalanceText = CoinAmount.Format(cache.ConfirmedSats, Profile.CoinUnit);
+        UnconfirmedText = cache.UnconfirmedSats != 0
+            ? $"+ {CoinAmount.Format(cache.UnconfirmedSats)} non confermato"
+            : "";
+        ReceiveAddress = _account.GetReceiveAddress(cache.NextReceiveIndex).ToString();
+        History.Clear();
+        foreach (var tx in cache.History)
+            History.Add(new HistoryRow(
+                tx.Height > 0 ? tx.Height.ToString() : "mempool",
+                (tx.DeltaSats >= 0 ? "+" : "") + CoinAmount.Format(tx.DeltaSats),
+                tx.Txid,
+                tx.Verified ? "✓ SPV" : "—"));
+    }
+
+    // ---------- comandi wallet ----------
+
+    [RelayCommand]
+    private async Task ConnectAndSync()
+    {
+        if (_account is null || _doc is null)
+            return;
+        IsSyncing = true;
+        StatusMessage = "";
+        try
+        {
+            if (_client is null || !_client.IsConnected)
+            {
+                var (host, port) = ParseServer();
+                ConnectionStatus = $"connessione a {host}:{port}…";
+                var pins = new CertificatePinStore(AppPaths.CertificatePinsPath(Net));
+                _client = await ElectrumClient.ConnectAsync(host, port, UseSsl, pins);
+                _client.NotificationReceived += OnServerNotification;
+                _client.Disconnected += _ => Dispatcher.UIThread.Post(() =>
+                    ConnectionStatus = "disconnesso");
+                ConnectionStatus = $"connesso a {host}:{port}{(UseSsl ? " (TLS)" : "")}";
+            }
+
+            var sync = new WalletSynchronizer(_account, _client, _doc.GapLimit);
+            sync.Progress += msg => Dispatcher.UIThread.Post(() => StatusMessage = msg);
+            var result = await sync.SyncOnceAsync();
+            _lastTransactions = result.Transactions;
+
+            _doc.Cache = new SyncCache
+            {
+                TipHeight = result.TipHeight,
+                ConfirmedSats = result.ConfirmedSats,
+                UnconfirmedSats = result.UnconfirmedSats,
+                NextReceiveIndex = result.NextReceiveIndex,
+                NextChangeIndex = result.NextChangeIndex,
+                History = [.. result.History],
+                Utxos = [.. result.Utxos],
+            };
+            WalletStore.Save(_doc, _walletPath!, _password);
+            ApplyCache(_doc.Cache);
+            StatusMessage = $"Sincronizzato: altezza {result.TipHeight}, " +
+                $"{result.History.Count} transazioni verificate SPV.";
+        }
+        catch (CertificatePinMismatchException ex)
+        {
+            ConnectionStatus = "certificato cambiato";
+            StatusMessage = ex.Message;
+        }
+        catch (Exception ex)
+        {
+            ConnectionStatus = "errore";
+            StatusMessage = $"Errore: {ex.Message}";
+        }
+        finally
+        {
+            IsSyncing = false;
+        }
+    }
+
+    private void OnServerNotification(string method, System.Text.Json.JsonElement payload)
+    {
+        // Cambiamento su un nostro indirizzo o nuovo blocco: risincronizza.
+        if (method is "blockchain.scripthash.subscribe" or "blockchain.headers.subscribe")
+            Dispatcher.UIThread.Post(() =>
+            {
+                if (!IsSyncing)
+                    _ = ConnectAndSync();
+            });
+    }
+
+    [RelayCommand]
+    private void ResetCertificates()
+    {
+        new CertificatePinStore(AppPaths.CertificatePinsPath(Net)).ResetAll();
+        StatusMessage = "Certificati SSL azzerati: riprova la connessione.";
+    }
+
+    [RelayCommand]
+    private async Task PrepareSend()
+    {
+        if (_account is null || _doc?.Cache is null)
+        {
+            SendPreview = "Sincronizza prima di inviare.";
+            return;
+        }
+        try
+        {
+            if (_lastTransactions is null)
+            {
+                SendPreview = "Connettiti al server e sincronizza prima di inviare.";
+                return;
+            }
+
+            var destination = BitcoinAddress.Create(SendTo.Trim(), PalladiumNetworks.For(Net));
+            long amount = 0;
+            if (!SendAll && !CoinAmount.TryParseCoins(SendAmount, out amount))
+            {
+                SendPreview = "Importo non valido.";
+                return;
+            }
+            if (!decimal.TryParse(SendFeeRate, out var feeRate) || feeRate <= 0)
+            {
+                SendPreview = "Fee rate non valido.";
+                return;
+            }
+
+            _pendingSend = new TransactionFactory(_account).Build(
+                _doc.Cache.Utxos, _lastTransactions, destination, amount, feeRate,
+                _doc.Cache.NextChangeIndex, SendAll);
+
+            SendPreview = $"txid {_pendingSend.Txid[..16]}… · " +
+                $"fee {CoinAmount.Format(_pendingSend.Fee.Satoshi, Profile.CoinUnit)} " +
+                $"({_pendingSend.Transaction.GetVirtualSize()} vB)" +
+                (_pendingSend.Signed ? "" : " · NON firmata (watch-only)");
+            HasPendingSend = _pendingSend.Signed;
+        }
+        catch (Exception ex)
+        {
+            _pendingSend = null;
+            HasPendingSend = false;
+            SendPreview = $"Errore: {ex.Message}";
+        }
+        await Task.CompletedTask;
+    }
+
+    [RelayCommand]
+    private async Task ConfirmSend()
+    {
+        if (_pendingSend is null || _client is null)
+            return;
+        try
+        {
+            var txid = await _client.BroadcastAsync(_pendingSend.ToHex());
+            SendPreview = $"Trasmessa: {txid}";
+            SendTo = SendAmount = "";
+            _pendingSend = null;
+            HasPendingSend = false;
+            await ConnectAndSync();
+        }
+        catch (Exception ex)
+        {
+            SendPreview = $"Errore broadcast: {ex.Message}";
+        }
+    }
+
+    [RelayCommand]
+    private void CloseWallet()
+    {
+        _ = _client?.DisposeAsync().AsTask();
+        _client = null;
+        _doc = null;
+        _account = null;
+        _lastTransactions = null;
+        _pendingSend = null;
+        HasPendingSend = false;
+        History.Clear();
+        IsWalletOpen = false;
+        ConnectionStatus = "non connesso";
+        RefreshSetupState();
+    }
+
+    private (string Host, int Port) ParseServer()
+    {
+        var parts = ServerInput.Trim().Split(':');
+        var host = parts[0];
+        var port = parts.Length > 1 && int.TryParse(parts[1], out var p)
+            ? p
+            : UseSsl ? Profile.DefaultSslPort : Profile.DefaultTcpPort;
+        return (host, port);
+    }
+}

src/App/ViewModels/ViewModelBase.cs

@@ -0,0 +1,7 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace PalladiumWallet.App.ViewModels;
+
+public abstract class ViewModelBase : ObservableObject
+{
+}

src/App/Views/MainWindow.axaml

@@ -0,0 +1,152 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:vm="using:PalladiumWallet.App.ViewModels"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        mc:Ignorable="d" d:DesignWidth="900" d:DesignHeight="620"
+        x:Class="PalladiumWallet.App.Views.MainWindow"
+        x:DataType="vm:MainWindowViewModel"
+        Icon="/Assets/avalonia-logo.ico"
+        Width="900" Height="620"
+        Title="Palladium Wallet">
+
+    <Design.DataContext>
+        <vm:MainWindowViewModel/>
+    </Design.DataContext>
+
+    <Grid RowDefinitions="*,Auto">
+
+        <!-- ============ PANNELLO SETUP: crea / ripristina / apri ============ -->
+        <ScrollViewer Grid.Row="0" IsVisible="{Binding IsSetupVisible}">
+            <StackPanel MaxWidth="560" Margin="24" Spacing="14">
+                <TextBlock Text="Palladium Wallet" FontSize="28" FontWeight="Bold"/>
+
+                <StackPanel Orientation="Horizontal" Spacing="10">
+                    <TextBlock Text="Rete:" VerticalAlignment="Center"/>
+                    <ComboBox ItemsSource="{Binding Networks}"
+                              SelectedItem="{Binding SelectedNetwork}"
+                              MinWidth="140"/>
+                </StackPanel>
+
+                <!-- Apri wallet esistente -->
+                <Border IsVisible="{Binding WalletFileExists}"
+                        BorderBrush="{DynamicResource SystemAccentColor}" BorderThickness="1"
+                        CornerRadius="6" Padding="14">
+                    <StackPanel Spacing="8">
+                        <TextBlock Text="Apri il wallet esistente" FontWeight="Bold"/>
+                        <TextBox PlaceholderText="Password del file (vuoto se non impostata)"
+                                 PasswordChar="●" Text="{Binding PasswordInput}"/>
+                        <Button Content="Apri wallet" Command="{Binding OpenExistingCommand}"/>
+                    </StackPanel>
+                </Border>
+
+                <!-- Crea / ripristina -->
+                <Border BorderBrush="Gray" BorderThickness="1" CornerRadius="6" Padding="14">
+                    <StackPanel Spacing="8">
+                        <TextBlock Text="Crea nuovo o ripristina da seed" FontWeight="Bold"/>
+                        <TextBox PlaceholderText="Mnemonica BIP39 (12 o 24 parole)"
+                                 AcceptsReturn="False" Text="{Binding MnemonicInput}"/>
+                        <Button Content="Genera nuova mnemonica" Command="{Binding GenerateMnemonicCommand}"/>
+                        <TextBox PlaceholderText="Passphrase BIP39 opzionale (cambia il wallet! annotala a parte)"
+                                 Text="{Binding PassphraseInput}"/>
+                        <TextBox PlaceholderText="Password di cifratura del file wallet (consigliata)"
+                                 PasswordChar="●" Text="{Binding PasswordInput}"/>
+                        <Button Content="Crea / ripristina wallet" Command="{Binding CreateOrRestoreCommand}"/>
+                    </StackPanel>
+                </Border>
+            </StackPanel>
+        </ScrollViewer>
+
+        <!-- ============ PANNELLO WALLET ============ -->
+        <Grid Grid.Row="0" RowDefinitions="Auto,Auto,*" IsVisible="{Binding IsWalletOpen}" Margin="16">
+
+            <!-- Testata: saldo + rete + chiudi -->
+            <Grid Grid.Row="0" ColumnDefinitions="*,Auto">
+                <StackPanel Grid.Column="0" Spacing="2">
+                    <TextBlock Text="{Binding BalanceText}" FontSize="30" FontWeight="Bold"/>
+                    <TextBlock Text="{Binding UnconfirmedText}" Foreground="Orange"/>
+                    <TextBlock Text="{Binding NetworkInfo}" FontSize="12" Foreground="Gray"/>
+                </StackPanel>
+                <Button Grid.Column="1" Content="Chiudi wallet" VerticalAlignment="Top"
+                        Command="{Binding CloseWalletCommand}"/>
+            </Grid>
+
+            <!-- Server -->
+            <Border Grid.Row="1" Margin="0,12,0,12" Padding="10"
+                    BorderBrush="Gray" BorderThickness="1" CornerRadius="6">
+                <Grid ColumnDefinitions="Auto,*,Auto,Auto,Auto,Auto">
+                    <TextBlock Grid.Column="0" Text="Server:" VerticalAlignment="Center" Margin="0,0,8,0"/>
+                    <TextBox Grid.Column="1" Text="{Binding ServerInput}"
+                             PlaceholderText="host:porta del server di indicizzazione"/>
+                    <CheckBox Grid.Column="2" Content="TLS" IsChecked="{Binding UseSsl}" Margin="8,0"/>
+                    <Button Grid.Column="3" Content="Connetti e sincronizza"
+                            Command="{Binding ConnectAndSyncCommand}" IsEnabled="{Binding !IsSyncing}"/>
+                    <Button Grid.Column="4" Content="Reset cert." Margin="6,0,0,0"
+                            Command="{Binding ResetCertificatesCommand}"/>
+                    <TextBlock Grid.Column="5" Text="{Binding ConnectionStatus}"
+                               VerticalAlignment="Center" Margin="10,0,0,0" Foreground="Gray"/>
+                </Grid>
+            </Border>
+
+            <!-- Tab: Ricevi / Storico / Invia -->
+            <TabControl Grid.Row="2">
+                <TabItem Header="Ricevi">
+                    <StackPanel Spacing="10" Margin="8">
+                        <TextBlock Text="Prossimo indirizzo non usato:"/>
+                        <SelectableTextBlock Text="{Binding ReceiveAddress}"
+                                             FontFamily="monospace" FontSize="16"/>
+                        <TextBlock Text="Ogni pagamento ricevuto qui comparirà nello storico alla prossima sincronizzazione."
+                                   Foreground="Gray" FontSize="12" TextWrapping="Wrap"/>
+                    </StackPanel>
+                </TabItem>
+
+                <TabItem Header="Storico">
+                    <ListBox ItemsSource="{Binding History}" Margin="4">
+                        <ListBox.ItemTemplate>
+                            <DataTemplate x:DataType="vm:HistoryRow">
+                                <Grid ColumnDefinitions="90,160,*,70">
+                                    <TextBlock Grid.Column="0" Text="{Binding Conferma}" Foreground="Gray"/>
+                                    <TextBlock Grid.Column="1" Text="{Binding Importo}" FontFamily="monospace"/>
+                                    <SelectableTextBlock Grid.Column="2" Text="{Binding Txid}"
+                                                         FontFamily="monospace" FontSize="12"/>
+                                    <TextBlock Grid.Column="3" Text="{Binding Verificata}" Foreground="Green"/>
+                                </Grid>
+                            </DataTemplate>
+                        </ListBox.ItemTemplate>
+                    </ListBox>
+                </TabItem>
+
+                <TabItem Header="Invia">
+                    <StackPanel Spacing="10" Margin="8" MaxWidth="640" HorizontalAlignment="Left">
+                        <TextBox PlaceholderText="Indirizzo destinatario" Text="{Binding SendTo}"
+                                 FontFamily="monospace"/>
+                        <Grid ColumnDefinitions="*,Auto,Auto">
+                            <TextBox Grid.Column="0" PlaceholderText="Importo (es. 1.5)"
+                                     Text="{Binding SendAmount}" IsEnabled="{Binding !SendAll}"/>
+                            <CheckBox Grid.Column="1" Content="Invia tutto" Margin="10,0"
+                                      IsChecked="{Binding SendAll}"/>
+                            <StackPanel Grid.Column="2" Orientation="Horizontal" Spacing="6">
+                                <TextBlock Text="fee sat/vB:" VerticalAlignment="Center"/>
+                                <TextBox Text="{Binding SendFeeRate}" MinWidth="60"/>
+                            </StackPanel>
+                        </Grid>
+                        <StackPanel Orientation="Horizontal" Spacing="10">
+                            <Button Content="Prepara transazione" Command="{Binding PrepareSendCommand}"/>
+                            <Button Content="CONFERMA E TRASMETTI" Classes="accent"
+                                    Command="{Binding ConfirmSendCommand}"
+                                    IsEnabled="{Binding HasPendingSend}"/>
+                        </StackPanel>
+                        <SelectableTextBlock Text="{Binding SendPreview}" TextWrapping="Wrap"
+                                             FontSize="13"/>
+                    </StackPanel>
+                </TabItem>
+            </TabControl>
+        </Grid>
+
+        <!-- Barra di stato -->
+        <Border Grid.Row="1" Background="{DynamicResource SystemControlBackgroundChromeMediumBrush}"
+                Padding="10,6">
+            <TextBlock Text="{Binding StatusMessage}" FontSize="12" TextWrapping="Wrap"/>
+        </Border>
+    </Grid>
+</Window>

src/App/Views/MainWindow.axaml.cs

@@ -0,0 +1,11 @@
+using Avalonia.Controls;
+
+namespace PalladiumWallet.App.Views;
+
+public partial class MainWindow : Window
+{
+    public MainWindow()
+    {
+        InitializeComponent();
+    }
+}

src/App/app.manifest

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1">
+  <!-- This manifest is used on Windows only.
+       Don't remove it as it might cause problems with window transparency and embedded controls.
+       For more details visit https://learn.microsoft.com/en-us/windows/win32/sbscs/application-manifests -->
+  <assemblyIdentity version="1.0.0.0" name="PalladiumWallet.App.Desktop"/>
+
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <!-- A list of the Windows versions that this application has been tested on
+           and is designed to work with. Uncomment the appropriate elements
+           and Windows will automatically select the most compatible environment. -->
+
+      <!-- Windows 10 -->
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
+    </application>
+  </compatibility>
+</assembly>