kf5: fix buttons not responding to first click

The sloppy focus timer was calling panePrompt.forceActiveFocus()
on mouse movement, stealing focus from button clicks. Remove the
auto-focus; add Ctrl+L shortcut to focus the prompt input instead.

gui/main-kf5.qml

@@ -1399,7 +1399,6 @@ ApplicationWindow {
                 interval: 100
                 onTriggered: {
                     paneRoot.focus = true
-                    panePrompt.forceActiveFocus()
                     // Update focused index
                     for (var i = 0; i < mainContent.panes.length; i++) {
                         if (mainContent.panes[i] === paneRoot) {
@@ -1409,6 +1408,12 @@ ApplicationWindow {
                     }
                 }
             }
+
+            // Ctrl+L focuses the prompt input (like browser URL bar)
+            Shortcut {
+                sequence: "Ctrl+L"
+                onActivated: panePrompt.forceActiveFocus()
+            }
         }
     }