QML: show daemon availability banner

Expose the Game Center daemon availability to the UI and show\nan inline error banner when it is not reachable, with a retry action.

src/qml/Main.qml

@@ -893,23 +893,45 @@ Kirigami.ApplicationWindow {
             }
         ]
 
-        LibraryView {
-            id: libraryView
+        ColumnLayout {
             anchors.fill: parent
+            spacing: 0
 
-            filterSource: root.currentSource
-            searchActive: root.searchActive
-
-            adaptiveCardSize: root.adaptiveCardSize
-            isTouchDevice: root.isTouchDevice
-
-            onGameSelected: function(game) {
-                root.selectedGame = game
-                detailsSheet.open()
+            Kirigami.InlineMessage {
+                id: daemonBanner
+                Layout.fillWidth: true
+                Layout.bottomMargin: Kirigami.Units.smallSpacing
+                type: Kirigami.MessageType.Error
+                visible: !App.launcher.daemonAvailable
+                text: i18n("Game Center daemon is not running. Game launching is unavailable.")
+                actions: [
+                    Kirigami.Action {
+                        text: i18n("Retry")
+                        icon.name: "view-refresh"
+                        onTriggered: App.launcher.retryDaemonConnection()
+                    }
+                ]
             }
 
-            onGameLaunched: function(game) {
-                App.launcher.launchGame(game)
+            LibraryView {
+                id: libraryView
+                Layout.fillWidth: true
+                Layout.fillHeight: true
+
+                filterSource: root.currentSource
+                searchActive: root.searchActive
+
+                adaptiveCardSize: root.adaptiveCardSize
+                isTouchDevice: root.isTouchDevice
+
+                onGameSelected: function(game) {
+                    root.selectedGame = game
+                    detailsSheet.open()
+                }
+
+                onGameLaunched: function(game) {
+                    App.launcher.launchGame(game)
+                }
             }
         }
     }