qt: HD wallet status indicator in status bar

Add a [HD] label next to the lock icon that shows whether the
wallet has a BIP39 HD seed active:
  - Red (#f26522, TRI brand color) when HD is enabled
  - Grey (#555555) when wallet is non-HD (legacy key pool)

Tooltip on hover explains what HD means and what the user must
back up to be able to restore the wallet.

Wired through a new updateHDStatus() slot that reads the
public WalletModel::hdEnabled() accessor and is called when
the wallet model is set. Lives in the icon cluster of the
status bar; the .onion and .b32.i2p address text sits in a
separate group on the right, so no crowding.

Closes the visible-state gap: the wallet already supported
HD seeds (BIP39/BIP32) and had a hdseeddialog, but there was
no visual confirmation of HD status anywhere in the UI.

src/qt/forms/mainwindow.ui

@@ -1663,6 +1663,23 @@ QProgressBar::chunk {
            </property>
           </widget>
          </item>
+         <item>
+          <widget class="QLabel" name="label_hd">
+           <property name="font">
+            <font>
+             <pointsize>9</pointsize>
+             <weight>75</weight>
+             <bold>true</bold>
+            </font>
+           </property>
+           <property name="toolTip">
+            <string>HD (BIP39) wallet seed status</string>
+           </property>
+           <property name="text">
+            <string notr="true">HD</string>
+           </property>
+          </widget>
+         </item>
          <item>
           <widget class="QLabel" name="label_staking">
            <property name="text">

src/qt/trianglesgui.cpp

@@ -359,6 +359,11 @@ TrianglesGUI::TrianglesGUI(bool fIsTestnet, QWidget *parent):
     labelV3Icon = ui->label_v3;
     labelV3Icon->setVisible(false);
 
+    // HD indicator next to lock icon (always visible; color reflects state)
+    labelHdIcon = ui->label_hd;
+    labelHdIcon->setVisible(true);
+    updateHDStatus();
+
     // Tor icon next to onion address in the stacked address group (hidden until populated)
     labelTorIcon = ui->label_tor_icon;
     labelTorIcon->setVisible(false);
@@ -650,6 +655,9 @@ void TrianglesGUI::setWalletModel(WalletModel *walletModel)
         connect(walletModel, SIGNAL(transactionSyncProgressChanged(bool,int)), this, SLOT(setWalletTransactionSyncProgress(bool,int)));
         setWalletTransactionSyncState(walletModel->isTransactionSyncing());
 
+        // HD status reflects wallet capability — refresh whenever the wallet model changes
+        updateHDStatus();
+
         // Balloon pop-up for new transaction
         connect(walletModel->getTransactionTableModel(), SIGNAL(rowsInserted(QModelIndex,int,int)),
                 this, SLOT(incomingTransaction(QModelIndex,int,int)));
@@ -1866,16 +1874,38 @@ void TrianglesGUI::updateI2PAddress()
         labelI2PIcon->setVisible(false);
     }
 
+    // I2P address text
     if (!hasI2P) {
         labelI2PAddress->setVisible(false);
         return;
     }
-
     labelI2PAddress->setText(QString::fromStdString(i2pAddress));
     labelI2PAddress->setToolTip(tr("This node's I2P .b32.i2p address. Click to copy."));
     labelI2PAddress->setVisible(true);
 }
 
+void TrianglesGUI::updateHDStatus()
+{
+    // Red (#f26522 — TRI brand color) when HD is enabled, grey when not.
+    // Placed next to the lock icon as a wallet-capability indicator.
+    if (!labelHdIcon) return;
+
+    bool fHD = false;
+    if (walletModel) {
+        fHD = walletModel->hdEnabled();
+    }
+
+    if (fHD) {
+        labelHdIcon->setStyleSheet("color: #f26522; font-weight: bold;");
+        labelHdIcon->setToolTip(tr("HD wallet: BIP39 seed active. Backup your seed phrase — individual keys alone will not restore this wallet."));
+    } else {
+        labelHdIcon->setStyleSheet("color: #555555; font-weight: bold;");
+        labelHdIcon->setToolTip(tr("Non-HD wallet: backup each address key separately. Use hdnew to upgrade to an HD seed."));
+    }
+    labelHdIcon->setText(QStringLiteral("HD"));
+    labelHdIcon->setVisible(true);
+}
+
 
 void TrianglesGUI::on_bHelp_clicked()
 {    

src/qt/trianglesgui.h

@@ -114,6 +114,7 @@ private:
     QLabel *labelV3Icon;
     QLabel *labelI2PIcon;
     QLabel *labelTorIcon;
+    QLabel *labelHdIcon;
     QLabel *progressBarLabel;
     QProgressBar *progressBar;
 
@@ -182,6 +183,7 @@ public slots:
     void setWalletTransactionSyncProgress(bool syncing, int pendingNotifications);
     void updateOnionAddress();
     void updateI2PAddress();
+    void updateHDStatus();
 
     /** Notify the user of an error in the network or transaction handling code. */
     void error(const QString &title, const QString &message, bool modal);