Add name to threads

This help identifying threads when debugging.
The naming scheme is using 'class/function name + variable name'.
Note that the length limitaion is 16 chars on linux. On Windows, the limit is 32767 chars.

PR #21403.

src/gui/torrentcreatordialog.cpp

@@ -109,6 +109,7 @@ TorrentCreatorDialog::TorrentCreatorDialog(QWidget *parent, const Path &defaultP
     updateInputPath(defaultPath);
 
     m_threadPool.setMaxThreadCount(1);
+    m_threadPool.setObjectName("TorrentCreatorDialog m_threadPool");
 
 #ifdef QBT_USES_LIBTORRENT2
     m_ui->checkOptimizeAlignment->hide();