fix: restore setAlwaysOnTop(true) — fixes GUI opening in separate space in fullscreen

Root cause: commit 0632681 removed setAlwaysOnTop(true) and replaced it
with manual objc_msgSend level tricks. Those tricks don't keep the window
in the same Space as Ableton when fullscreen.

Fix: put back setAlwaysOnTop(true) + keep the X button fix (closeButtonPressed
hides window instead of quitting). Removed all objc_msgSend hacks.

Source/Helper/HelperPluginHost.cpp

@@ -4,12 +4,7 @@
 #include <pthread.h>
 #include <sched.h>
 
-#if JUCE_MAC
-#include <objc/objc.h>
-#include <objc/message.h>
-#endif
-
-// Custom window
+// Custom window — X button hides instead of quitting
 class PluginGuiWindow : public juce::DocumentWindow
 {
 public:
@@ -264,6 +259,7 @@ void HelperPluginHost::showGui()
         guiWindow = std::make_unique<PluginGuiWindow>(plugin->getName());
         guiWindow->setContentOwned(editor, true);
         guiWindow->setResizable(true, true);
+        guiWindow->setAlwaysOnTop(true);
         guiWindow->centreWithSize(editor->getWidth(), editor->getHeight());
         guiWindow->setVisible(true);
     });