Add identity management

Manage several TeamSpeak identities like the official client instead of
using one auto-generated identity file.

- IdentityStore/IdentityEntry keep each identity as a TeamSpeak-format INI
  in ~/.ts3jclient/identities, so files interchange with the TS3 client;
  supports create, import, export, rename, remove and a cancellable
  security-level search. A legacy identity.ini is migrated in on first load.
- Settings hold the default identity; bookmarks may pin their own, falling
  back to the default when unset.
- TeamspeakConnection now connects with the identity it is handed.
- Swing: Tools -> Identities manager, plus an identity drop-down in the
  connect and bookmark forms.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

ts3-client/swing/src/main/java/com/ts3client/ui/BookmarksDialog.java

@@ -2,6 +2,7 @@ package com.ts3client.ui;
 
 import com.ts3client.config.Bookmark;
 import com.ts3client.config.Bookmarks;
+import com.ts3client.config.IdentityStore;
 
 import javax.swing.BorderFactory;
 import javax.swing.Box;
@@ -26,14 +27,17 @@ import java.util.function.Consumer;
 public final class BookmarksDialog extends JDialog {
 
     private final Bookmarks bookmarks;
+    private final IdentityStore identities;
     private final Consumer<Bookmark> onConnect;
     private final Runnable onChanged;
     private final DefaultListModel<Bookmark> listModel = new DefaultListModel<>();
     private final JList<Bookmark> list = new JList<>(listModel);
 
-    public BookmarksDialog(Frame owner, Bookmarks bookmarks, Consumer<Bookmark> onConnect, Runnable onChanged) {
+    public BookmarksDialog(Frame owner, Bookmarks bookmarks, IdentityStore identities,
+                           Consumer<Bookmark> onConnect, Runnable onChanged) {
         super(owner, "Manage Bookmarks", true);
         this.bookmarks = bookmarks;
+        this.identities = identities;
         this.onConnect = onConnect;
         this.onChanged = onChanged;
 
@@ -120,6 +124,7 @@ public final class BookmarksDialog extends JDialog {
         JTextField port = new JTextField(Integer.toString(b.port));
         JTextField nick = new JTextField(b.nickname == null ? "" : b.nickname);
         JPasswordField password = new JPasswordField(b.password == null ? "" : b.password);
+        IdentityChooser identity = new IdentityChooser(identities, true, b.identityId);
 
         JPanel form = new JPanel(new GridLayout(0, 1, 0, 2));
         form.add(new JLabel("Label:"));
@@ -132,6 +137,8 @@ public final class BookmarksDialog extends JDialog {
         form.add(nick);
         form.add(new JLabel("Password (optional):"));
         form.add(password);
+        form.add(new JLabel("Identity:"));
+        form.add(identity);
 
         int result = JOptionPane.showConfirmDialog(this, form,
                 "Bookmark", JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE);
@@ -150,6 +157,7 @@ public final class BookmarksDialog extends JDialog {
         }
         b.nickname = nick.getText().trim();
         b.password = new String(password.getPassword());
+        b.identityId = identity.getSelectedIdentityId();
         return true;
     }
 }