Replicate the new moveIntoGroup behavior

Hyprland has updated some of the core functions related to groupping
windows in PR: https://github.com/hyprwm/Hyprland/pull/2630

Specifically, the CWindow::insertWindowIntoGroup was updated to no
longer automatically make the newly inserted window the group's head,
allowing to insert windows without the group auto-focusing them.

With that, the CKeybindManager::moveIntoGroup (dispatcher) function was
then updated to adhere to the change in insertWindowIntoGroup and to
make the inserted widow the group's head from there.

It's probably possible to utilize the insertWindowIntoGroup without
making the inserted window the group's head in a more clever way,
however for now, this commit just changes our logic in groupCreate
function to fully replicate the moveIntoGroup for each dwindle child
node window.

This means we're still doing what we were doing before, that is to
insert a window, make it the group head, repeat for each dwindle child
and at the end make the original group head the head again.

The reason this fix doesn't simply skip making each of the nodes a group
head is that without it, the layout doesn't seem to properly recognize
that the window should no longer be shown, and while this probably can
be addressed by replicating some of the CWindow::setGroupCurrent
function's behavior, for now, that's a task for later.

src/main.cpp

@@ -73,11 +73,29 @@ void groupCreate(const SDwindleNodeData* PNODE, CHyprDwindleLayout* layout)
     }
 
     // Add all of the children nodes into the group
+    // (This is mostly copied logic from CKeybindManager::moveIntoGroup. Note that it
+    // includes support for the child node to be in another group, in which case only
+    // this window if moved out of that group and into this one. We don't actually
+    // need this logic now, because we don't support nested groups though)
     for (auto& n : newGroupMembers) {
         auto window = n->pWindow;
-        layout->onWindowRemoved(window);
+
-        PWINDOW->insertWindowToGroup(window);
+        // Create a group bar decoration for the window
+        // (assuming it's not already in a group, in which case it should have one)
+        if (!window->m_sGroupData.pNextWindow)
             window->m_dWindowDecorations.emplace_back(std::make_unique<CHyprGroupBarDecoration>(window));
+
+        g_pLayoutManager->getCurrentLayout()->onWindowRemoved(window); // This removes groupped property!
+
+        window->m_sGroupData.locked = false;
+        window->m_sGroupData.head = false;
+
+        PWINDOW->insertWindowToGroup(window);
+        PWINDOW->setGroupCurrent(window);
+        window->updateWindowDecos();
+
+        g_pLayoutManager->getCurrentLayout()->recalculateWindow(window);
+        g_pCompositor->focusWindow(window);
     }
 
     // Moving new windows into group makes them the active window in that group,