jfjoch_viewer: a broker URL given on the command line opens following the collection

`jfjoch_viewer http://<broker>` opened image 0, and for an HTTP source any image number
>= 0 sets the autoload mode to None (JFJochImageReadingWorker::LoadFile_i), so the viewer
showed the first image and never updated - no new images, plots or image count, with every
receiver. The URL dialog already asks for image -1 (follow live); the command line now does
the same for http:// and https://, and still opens a file at its first image.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HVeDQsU5a8AJUdJPgWevAK

viewer/JFJochViewerWindow.cpp

@@ -716,8 +716,11 @@ JFJochViewerWindow::JFJochViewerWindow(QWidget *parent, bool dbus, const QString
     menuBar->AddViewToggle(toolBarDisplay->backgroundSliderAction());
     toolBarDisplay->showBackgroundSlider(settings.value("backgroundSlider", false).toBool());
 
-    if (!file.isEmpty())
-        LoadFile(file, 0, 1, false);
+    // A broker URL opens following the collection (image -1), as the URL dialog does; a file opens at its first image.
+    if (!file.isEmpty()) {
+        const bool http = file.startsWith("http://") || file.startsWith("https://");
+        LoadFile(file, http ? -1 : 0, 1, false);
+    }
 }
 
 JFJochViewerWindow::~JFJochViewerWindow() {