Baseline for wino-mail-dtkqt UI migration

src/ui/mainmainwindow.cpp

@@ -164,12 +164,21 @@ void MainMainWindow::setupMailPage() {
     m_mailListView = new MailListView();
     connect(m_mailListView, &MailListView::emailSelected, this, &MainMainWindow::onEmailSelected);
     connect(m_mailListView, &MailListView::composeRequested, this, &MainMainWindow::onComposeRequested);
+    connect(m_mailListView, &MailListView::emailOpenRequested, this, [this](int mailId) {
+        openMailInIndependentWindow(mailId);
+    });
     m_folderSplitter->addWidget(m_mailListView);
 
     // Reader
     m_emailViewer = new ReaderView();
     m_emailViewer->setMinimumWidth(350);
     connect(m_emailViewer, &ReaderView::replyRequested, this, &MainMainWindow::onReaderReplyRequested);
+    connect(m_emailViewer, &ReaderView::detachRequested, this, [this]() {
+        std::optional<MailItem> currentItem = MailItemDao::findById(m_emailModel->getCurrentMailId());
+        if (currentItem) {
+            openMailInIndependentWindow(currentItem->id());
+        }
+    });
     m_folderSplitter->addWidget(m_emailViewer);
 
     // Default sizes: folder 240, list 380, reader flex
@@ -248,6 +257,24 @@ void MainMainWindow::onNewMessage() {
     switchToPage(PageCompose);
 }
 
+void MainMainWindow::openMailInIndependentWindow(int mailId) {
+    std::optional<MailItem> item = MailItemDao::findById(mailId);
+    if (!item.has_value()) return;
+
+    QMainWindow *detachedWin = new QMainWindow();
+    detachedWin->setWindowTitle(QString("Mail - %1").arg(item->subject()));
+    
+    ReaderView *detachedReader = new ReaderView();
+    detachedReader->setMailItem(&item.value());
+    
+    detachedWin->setCentralWidget(detachedReader);
+    detachedWin->resize(800, 600);
+    detachedWin->setAttribute(Qt::WA_DeleteOnClose);
+    detachedWin->show();
+    
+    statusBar()->showMessage("Opened mail in independent window", 3000);
+}
+
 void MainMainWindow::createToolBar() {
     m_toolBar = addToolBar("Main Toolbar");
     m_toolBar->setMovable(false);