feat(gui): split server discovery into its own always-usable button

Previously the server settings overlay had only "Connect and sync" and
"Reset certs" — peer discovery had no button and only ran implicitly
when reopening the dialog while connected. Add a dedicated "Sincronizza"
button wired to DiscoverServersCommand, and make it work even without
an active connection by opening a short-lived connection to a candidate
server just to query its peer list, then closing it without touching
the wallet's connection state.

src/App/Localization/Loc.cs

@@ -169,9 +169,9 @@ public sealed class Loc
         // Wallet panel
         ["wallet.close"]          = ["Chiudi wallet",                                                     "Close wallet",                 "Cerrar wallet",                        "Fermer le wallet",                         "Fechar carteira",                          "Wallet schließen"],
         ["wallet.server"]         = ["Server:",                                                           "Server:",                      "Servidor:",                            "Serveur :",                                "Servidor:",                                "Server:"],
-        ["wallet.connect"]        = ["Connetti e sincronizza",                                            "Connect and sync",             "Conectar y sincronizar",               "Connecter et synchroniser",                "Conectar e sincronizar",                   "Verbinden und synchronisieren"],
+        ["wallet.connect"]        = ["Connetti",                                                          "Connect",                       "Conectar",                             "Connecter",                                "Conectar",                                  "Verbinden"],
         ["wallet.manual"]         = ["oppure host:porta manuale",                                         "or manual host:port",          "o host:puerto manual",                 "ou hôte:port manuel",                      "ou host:porta manual",                     "oder manuell host:port"],
-        ["wallet.discover"]       = ["Cerca altri server",                                                "Discover servers",             "Buscar otros servidores",              "Rechercher des serveurs",                  "Procurar servidores",                      "Server suchen"],
+        ["wallet.discover"]       = ["Sincronizza",                                                       "Sync servers",                  "Sincronizar",                          "Synchroniser",                             "Sincronizar",                              "Synchronisieren"],
         ["wallet.resetcert"]      = ["Reset cert.",                                                       "Reset certs",                  "Restablecer cert.",                    "Réinit. cert.",                            "Redefinir cert.",                          "Zert. zurücksetzen"],
         ["tab.receive"]           = ["Ricevi",                                                            "Receive",                      "Recibir",                              "Recevoir",                                 "Receber",                                  "Empfangen"],
         ["tab.history"]           = ["Storico",                                                           "History",                      "Historial",                            "Historique",                               "Histórico",                                "Verlauf"],
@@ -389,6 +389,7 @@ public sealed class Loc
         ["msg.height"]            = ["altezza",                                                           "height",                       "altura",                               "hauteur",                                  "altura",                                   "Höhe"],
         ["msg.pending"]           = ["in attesa di conferma",                                             "pending confirmation",         "pendiente de confirmación",            "en attente de confirmation",               "aguardando confirmação",                   "ausstehende Bestätigung"],
         ["msg.notspendable"]      = ["non ancora spendibile",                                             "not yet spendable",            "aún no gastable",                      "pas encore dépensable",                    "ainda não gastável",                       "noch nicht verwendbar"],
+        ["msg.immature"]          = ["in maturazione",                                                    "maturing",                      "en maduración",                        "en maturation",                            "em maturação",                             "in Reifung"],
         ["msg.settings.saved"]    = ["Impostazioni salvate.",                                             "Settings saved.",              "Configuración guardada.",              "Paramètres enregistrés.",                  "Configurações salvas.",                    "Einstellungen gespeichert."],
         ["msg.certreset"]         = [
             "Certificati SSL azzerati: riprova la connessione.",

src/App/ViewModels/MainWindowViewModel.Receive.cs

@@ -25,6 +25,9 @@ public partial class MainWindowViewModel
     [ObservableProperty]
     private string unconfirmedText = "";
 
+    [ObservableProperty]
+    private string immatureText = "";
+
     [ObservableProperty]
     private string networkInfo = "";
 
@@ -249,6 +252,7 @@ public partial class MainWindowViewModel
         {
             BalanceText = $"0.00000000 {Profile.CoinUnit}";
             UnconfirmedText = "";
+            ImmatureText = "";
             ReceiveAddress = _account.GetReceiveAddress(0).ToString();
             History.Clear();
             Addresses.Clear();
@@ -261,11 +265,14 @@ public partial class MainWindowViewModel
                     $"m/{_doc!.AccountPath}/0/{i}"));
             return;
         }
-        BalanceText = Fmt(cache.ConfirmedSats);
+        BalanceText = Fmt(cache.ConfirmedSats - cache.ImmatureSats);
         var pending = cache.History.Where(t => t.Height <= 0).Sum(t => t.DeltaSats);
         UnconfirmedText = pending != 0
             ? $"{Loc.Tr("msg.pending")}: {(pending > 0 ? "+" : "")}{Fmt(pending)} — {Loc.Tr("msg.notspendable")}"
             : "";
+        ImmatureText = cache.ImmatureSats != 0
+            ? $"{Loc.Tr("msg.immature")}: {Fmt(cache.ImmatureSats)} — {Loc.Tr("msg.notspendable")}"
+            : "";
         ReceiveAddress = _account.GetReceiveAddress(cache.NextReceiveIndex).ToString();
         History.Clear();
         foreach (var tx in cache.History)

src/App/ViewModels/MainWindowViewModel.Sync.cs

@@ -288,6 +288,7 @@ public partial class MainWindowViewModel
                     TipHeight = result.TipHeight,
                     ConfirmedSats = result.ConfirmedSats,
                     UnconfirmedSats = result.UnconfirmedSats,
+                    ImmatureSats = result.ImmatureSats,
                     NextReceiveIndex = result.NextReceiveIndex,
                     NextChangeIndex = result.NextChangeIndex,
                     History = [.. result.History],
@@ -344,17 +345,57 @@ public partial class MainWindowViewModel
             _ = ConnectAndSync();
     }
 
+    /// <summary>
+    /// Peer discovery. Always clickable: if the wallet is already connected, it reuses
+    /// that connection; otherwise it opens a short-lived connection to a candidate server
+    /// just to query its peer list, without touching the wallet's connection state.
+    /// </summary>
     [RelayCommand]
     private async Task DiscoverServers()
     {
-        if (_client is null || !_client.IsConnected)
+        if (_client is { IsConnected: true } connected)
         {
-            StatusMessage = Loc.Tr("conn.none") + ".";
+            await DiscoverServersUsing(connected);
+            return;
+        }
+
+        var (host, port) = ParseServer();
+        ElectrumClient? temp = null;
+        Exception? lastError = null;
+        foreach (var (h, p) in BuildServerCandidates(host, port))
+        {
+            try
+            {
+                var pins = new CertificatePinStore(AppPaths.CertificatePinsPath(Net));
+                temp = await ElectrumClient.ConnectAsync(h, p, UseSsl, pins);
+                lastError = null;
+                break;
+            }
+            catch (Exception ex)
+            {
+                lastError = ex;
+            }
+        }
+        if (temp is null)
+        {
+            StatusMessage = $"Errore nella scoperta peer: {lastError?.Message ?? Loc.Tr("conn.none")}";
             return;
         }
         try
         {
-            var added = await Registry.DiscoverAsync(_client);
+            await DiscoverServersUsing(temp);
+        }
+        finally
+        {
+            await temp.DisposeAsync();
+        }
+    }
+
+    private async Task DiscoverServersUsing(ElectrumClient client)
+    {
+        try
+        {
+            var added = await Registry.DiscoverAsync(client);
             var selected = SelectedKnownServer;
             RefreshServers();
             SelectedKnownServer = KnownServers.FirstOrDefault(s => s.Host == selected?.Host)

src/App/Views/MainView.axaml

@@ -314,6 +314,9 @@
                     <TextBlock Text="{Binding UnconfirmedText}" Foreground="#FCD34D"
                                TextWrapping="Wrap"
                                IsVisible="{Binding UnconfirmedText, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
+                    <TextBlock Text="{Binding ImmatureText}" Foreground="#FCD34D"
+                               TextWrapping="Wrap"
+                               IsVisible="{Binding ImmatureText, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
                     <TextBlock Text="{Binding NetworkInfo}" Classes="on-hero" FontSize="12"
                                Margin="0,2,0,0"/>
                 </StackPanel>
@@ -1234,6 +1237,8 @@
                     <StackPanel Orientation="Horizontal" Spacing="8" IsVisible="{Binding IsDesktop}">
                         <Button Content="{Binding Loc[wallet.connect]}" Classes="accent"
                                 Command="{Binding ConnectAndSyncCommand}"/>
+                        <Button Content="{Binding Loc[wallet.discover]}"
+                                Command="{Binding DiscoverServersCommand}"/>
                         <Button Content="{Binding Loc[wallet.resetcert]}"
                                 Command="{Binding ResetCertificatesCommand}"/>
                     </StackPanel>
@@ -1242,6 +1247,9 @@
                         <Button Content="{Binding Loc[wallet.connect]}" Classes="accent"
                                 Command="{Binding ConnectAndSyncCommand}"
                                 HorizontalAlignment="Stretch" HorizontalContentAlignment="Center"/>
+                        <Button Content="{Binding Loc[wallet.discover]}"
+                                Command="{Binding DiscoverServersCommand}"
+                                HorizontalAlignment="Stretch" HorizontalContentAlignment="Center"/>
                         <Button Content="{Binding Loc[wallet.resetcert]}"
                                 Command="{Binding ResetCertificatesCommand}"
                                 HorizontalAlignment="Stretch" HorizontalContentAlignment="Center"/>

src/Cli/Program.cs

@@ -104,8 +104,9 @@ static int Info(string[] o)
     Console.WriteLine($"xpub:     {doc.AccountXpub}");
     if (doc.Cache is { } cache)
     {
-        Console.WriteLine($"saldo:    {CoinAmount.Format(cache.ConfirmedSats, account.Profile.CoinUnit)} confermato"
-            + (cache.UnconfirmedSats != 0 ? $" + {CoinAmount.Format(cache.UnconfirmedSats)} in attesa (non spendibile)." : ""));
+        Console.WriteLine($"saldo:    {CoinAmount.Format(cache.ConfirmedSats - cache.ImmatureSats, account.Profile.CoinUnit)} spendibile"
+            + (cache.ImmatureSats != 0 ? $" + {CoinAmount.Format(cache.ImmatureSats)} in maturazione (non spendibile)" : "")
+            + (cache.UnconfirmedSats != 0 ? $" + {CoinAmount.Format(cache.UnconfirmedSats)} in attesa di conferma (non spendibile)." : ""));
         Console.WriteLine($"sync:     altezza {cache.TipHeight}, {cache.History.Count} transazioni");
         Console.WriteLine($"ricezione: {account.GetReceiveAddress(cache.NextReceiveIndex)}");
     }
@@ -147,6 +148,7 @@ static async Task<int> Sync(string[] o)
         TipHeight = result.TipHeight,
         ConfirmedSats = result.ConfirmedSats,
         UnconfirmedSats = result.UnconfirmedSats,
+        ImmatureSats = result.ImmatureSats,
         NextReceiveIndex = result.NextReceiveIndex,
         NextChangeIndex = result.NextChangeIndex,
         History = [.. result.History],
@@ -158,7 +160,8 @@ static async Task<int> Sync(string[] o)
     };
     WalletStore.Save(doc, path, Opt(o, "--password"));
 
-    Console.WriteLine($"Saldo: {CoinAmount.Format(result.ConfirmedSats, account.Profile.CoinUnit)} confermato"
+    Console.WriteLine($"Saldo: {CoinAmount.Format(result.ConfirmedSats - result.ImmatureSats, account.Profile.CoinUnit)} spendibile"
+        + (result.ImmatureSats != 0 ? $" + {CoinAmount.Format(result.ImmatureSats)} in maturazione (non spendibile)" : "")
         + (result.UnconfirmedSats != 0 ? $" + {CoinAmount.Format(result.UnconfirmedSats)} in attesa di conferma (non spendibile)" : ""));
     Console.WriteLine($"Storico ({result.History.Count}):");
     foreach (var tx in result.History)

src/Core/Spv/WalletSynchronizer.cs

@@ -5,6 +5,7 @@ using PalladiumWallet.Core.Chain;
 using PalladiumWallet.Core.Crypto;
 using PalladiumWallet.Core.Net;
 using PalladiumWallet.Core.Storage;
+using PalladiumWallet.Core.Wallet;
 
 namespace PalladiumWallet.Core.Spv;
 
@@ -21,6 +22,13 @@ public sealed class SyncResult
     public required int TipHeight { get; init; }
     public required long ConfirmedSats { get; init; }
     public required long UnconfirmedSats { get; init; }
+
+    /// <summary>
+    /// Confirmed but not yet spendable: coinbase outputs below maturity or regular
+    /// outputs below <see cref="Chain.ChainProfile.MinConfirmations"/>. Subset of
+    /// <see cref="ConfirmedSats"/>.
+    /// </summary>
+    public required long ImmatureSats { get; init; }
     public required int NextReceiveIndex { get; init; }
     public required int NextChangeIndex { get; init; }
     public required IReadOnlyList<CachedTx> History { get; init; }
@@ -276,6 +284,9 @@ public sealed class WalletSynchronizer(IWalletAccount account, ElectrumClient cl
             TipHeight        = tip.Height,
             ConfirmedSats    = utxos.Where(u => u.Height > 0).Sum(u => u.ValueSats),
             UnconfirmedSats  = utxos.Where(u => u.Height <= 0).Sum(u => u.ValueSats),
+            ImmatureSats     = utxos.Where(u =>
+                u.Height > 0 && u.Confirmations(tip.Height) < u.RequiredConfirmations(account.Profile))
+                .Sum(u => u.ValueSats),
             NextReceiveIndex = nextReceive,
             NextChangeIndex  = nextChange,
             History          = history,

src/Core/Storage/WalletDocument.cs

@@ -95,6 +95,9 @@ public sealed class SyncCache
     public int TipHeight { get; set; }
     public long ConfirmedSats { get; set; }
     public long UnconfirmedSats { get; set; }
+
+    /// <summary>Confirmed but not yet spendable (coinbase immature or under min confirmations). Subset of ConfirmedSats.</summary>
+    public long ImmatureSats { get; set; }
     public int NextReceiveIndex { get; set; }
     public int NextChangeIndex { get; set; }
     public List<CachedTx> History { get; set; } = [];

src/Core/Wallet/TransactionFactory.cs

@@ -52,20 +52,8 @@ public sealed class TransactionFactory(IWalletAccount account)
         int tipHeight,
         bool sendAll = false)
     {
-        var coinbaseMaturity = account.Profile.CoinbaseMaturity;
-        var minConf = account.Profile.MinConfirmations;
-
-        // A UTXO is spendable when it has enough confirmations:
-        //   - coinbase: COINBASE_MATURITY + 1 confirmations (matches the Qt wallet: the consensus
-        //     rule is nSpendHeight - nHeight >= 120, so at the current tip a TX can be mined in
-        //     the next block when tipHeight - height + 1 >= 121)
-        //   - regular: MinConfirmations (wallet policy, no consensus rule)
-        int coinbaseThreshold = coinbaseMaturity + 1;
-        var spendable = utxos.Where(u =>
-            !u.Frozen &&
-            u.Height > 0 &&
-            (tipHeight - u.Height + 1) >= (u.IsCoinbase ? coinbaseThreshold : minConf)
-        ).ToList();
+        var profile = account.Profile;
+        var spendable = utxos.Where(u => u.IsSpendable(profile, tipHeight)).ToList();
 
         if (spendable.Count == 0)
         {
@@ -77,20 +65,21 @@ public sealed class TransactionFactory(IWalletAccount account)
 
             var immature = utxos.Where(u =>
                 !u.Frozen && u.Height > 0 && u.IsCoinbase &&
-                (tipHeight - u.Height + 1) < coinbaseThreshold).ToList();
+                u.Confirmations(tipHeight) < u.RequiredConfirmations(profile)).ToList();
             if (immature.Count > 0)
             {
-                var best = immature.Max(u => tipHeight - u.Height + 1);
-                reasons.Append($"{immature.Count} coinbase output(s) not yet mature ({best}/{coinbaseThreshold} confirmations). ");
+                var best = immature.Max(u => u.Confirmations(tipHeight));
+                var threshold = profile.CoinbaseMaturity + 1;
+                reasons.Append($"{immature.Count} coinbase output(s) not yet mature ({best}/{threshold} confirmations). ");
             }
 
             var underConf = utxos.Where(u =>
                 !u.Frozen && u.Height > 0 && !u.IsCoinbase &&
-                (tipHeight - u.Height + 1) < minConf).ToList();
+                u.Confirmations(tipHeight) < u.RequiredConfirmations(profile)).ToList();
             if (underConf.Count > 0)
             {
-                var best = underConf.Max(u => tipHeight - u.Height + 1);
-                reasons.Append($"{underConf.Count} output(s) need {minConf} confirmations ({best} so far). ");
+                var best = underConf.Max(u => u.Confirmations(tipHeight));
+                reasons.Append($"{underConf.Count} output(s) need {profile.MinConfirmations} confirmations ({best} so far). ");
             }
 
             throw new WalletSpendException(reasons.Length > 0

src/Core/Wallet/UtxoSpendability.cs

@@ -0,0 +1,24 @@
+using PalladiumWallet.Core.Chain;
+using PalladiumWallet.Core.Storage;
+
+namespace PalladiumWallet.Core.Wallet;
+
+/// <summary>
+/// Confirmation-threshold rules shared between coin selection (<see cref="TransactionFactory"/>)
+/// and balance reporting: a coinbase output needs COINBASE_MATURITY + 1 confirmations
+/// (consensus rule nSpendHeight - nHeight >= 120, plus one block of safety margin, matching
+/// the Qt wallet); a regular output needs <see cref="ChainProfile.MinConfirmations"/> (wallet
+/// policy, no consensus rule).
+/// </summary>
+public static class UtxoSpendability
+{
+    public static int RequiredConfirmations(this CachedUtxo utxo, ChainProfile profile) =>
+        utxo.IsCoinbase ? profile.CoinbaseMaturity + 1 : profile.MinConfirmations;
+
+    public static int Confirmations(this CachedUtxo utxo, int tipHeight) =>
+        utxo.Height <= 0 ? 0 : tipHeight - utxo.Height + 1;
+
+    /// <summary>True when the UTXO has met its confirmation threshold and is not frozen.</summary>
+    public static bool IsSpendable(this CachedUtxo utxo, ChainProfile profile, int tipHeight) =>
+        !utxo.Frozen && utxo.Height > 0 && utxo.Confirmations(tipHeight) >= utxo.RequiredConfirmations(profile);
+}