feat: add DesktopMain.qml; make Main.qml mode-aware

Main.qml reads App.config.uiMode at startup:
- Config.Desktop: load DesktopMain.qml via Loader, normal window,
  save/restore window geometry from Config
- anything else (Couch/Auto): existing full-screen couch UI

DesktopMain.qml: SidebarView + LibraryView + GameDetailsSheet +
GameEditDialog + settings overlay.

src/CMakeLists.txt

@@ -104,6 +104,7 @@ ecm_add_qml_module(alakarte URI org.kde.alakarte
     VERSION 1.0
     QML_FILES
         qml/Main.qml
+        qml/DesktopMain.qml
         qml/LibraryView.qml
         qml/GameCard.qml
         qml/ConsoleGameDetail.qml

src/qml/DesktopMain.qml

@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// SPDX-FileCopyrightText: 2026 A-La-Karte Contributors
+
+import QtQuick
+import QtQuick.Controls as QQC2
+import QtQuick.Layouts
+import org.kde.kirigami as Kirigami
+import org.kde.alakarte
+import "components"
+
+Item {
+    id: desktopRoot
+
+    property string currentCategory: "all"
+    property string searchText: ""
+    property var selectedGame: null
+
+    RowLayout {
+        anchors.fill: parent
+        spacing: 0
+
+        ColumnLayout {
+            Layout.preferredWidth: 240
+            Layout.minimumWidth: 180
+            Layout.maximumWidth: 320
+            Layout.fillHeight: true
+            spacing: 0
+
+            SidebarView {
+                id: sidebar
+                Layout.fillWidth: true
+                Layout.fillHeight: true
+                currentSource: desktopRoot.currentCategory
+
+                onSourceSelected: function(src) { desktopRoot.currentCategory = src }
+                onSettingsRequested: settingsLoader.active = true
+                onImportRequested: App.importAllGames()
+                onHiddenGamesRequested: applySourceById("hidden")
+            }
+        }
+
+        Kirigami.Separator {
+            Layout.fillHeight: true
+        }
+
+        ColumnLayout {
+            Layout.fillWidth: true
+            Layout.fillHeight: true
+            spacing: 0
+
+            QQC2.ToolBar {
+                Layout.fillWidth: true
+
+                contentItem: RowLayout {
+                    spacing: Kirigami.Units.mediumSpacing
+
+                    QQC2.TextField {
+                        id: searchField
+                        Layout.fillWidth: true
+                        placeholderText: i18n("Search games…")
+                        onTextChanged: desktopRoot.searchText = text
+                        Keys.onEscapePressed: { text = ""; desktopRoot.searchText = "" }
+                    }
+                }
+            }
+
+            LibraryView {
+                id: libraryView
+                Layout.fillWidth: true
+                Layout.fillHeight: true
+                filterSource: desktopRoot.currentCategory
+                filterText: desktopRoot.searchText
+
+                onHeaderFocusRequested: sidebar.focusList()
+                onGameFocused: function(game) {}
+                onGameSelected: function(game) {
+                    desktopRoot.selectedGame = game
+                    gameDetailsSheet.open()
+                }
+                onGameLaunched: function(game) {
+                    App.launcher.launchGame(game)
+                }
+            }
+        }
+    }
+
+    GameDetailsSheet {
+        id: gameDetailsSheet
+        game: desktopRoot.selectedGame
+
+        onLaunchRequested: {
+            if (desktopRoot.selectedGame) App.launcher.launchGame(desktopRoot.selectedGame)
+            close()
+        }
+        onEditRequested: {
+            gameEditDialog.game = desktopRoot.selectedGame
+            gameEditDialog.isEditing = true
+            close()
+            gameEditDialog.open()
+        }
+        onRemoveRequested: {
+            if (desktopRoot.selectedGame) App.removeGame(desktopRoot.selectedGame)
+            desktopRoot.selectedGame = null
+            close()
+        }
+    }
+
+    GameEditDialog {
+        id: gameEditDialog
+    }
+
+    Loader {
+        id: settingsLoader
+        anchors.fill: parent
+        z: 20
+        active: false
+        sourceComponent: Item {
+            Rectangle {
+                anchors.fill: parent
+                color: Qt.rgba(0, 0, 0, 0.72)
+                TapHandler { onTapped: settingsLoader.active = false }
+            }
+            SettingsPage {
+                anchors.centerIn: parent
+                width: Math.min(parent.width - 48, 760)
+                height: Math.min(parent.height - 48, 680)
+            }
+            Keys.onEscapePressed: settingsLoader.active = false
+        }
+        onLoaded: item.forceActiveFocus()
+    }
+}

src/qml/Main.qml

@@ -17,6 +17,8 @@ Maui.ApplicationWindow {
     minimumWidth: 800
     minimumHeight: 500
 
+    readonly property bool isCouchMode: App.config.uiMode !== Config.Desktop
+
     property var focusedGame: null
     property var selectedGame: null
     property string currentCategory: "all"
@@ -25,16 +27,37 @@ Maui.ApplicationWindow {
     property bool settingsVisible: false
     property string searchText: ""
 
-    color: "#0d0d14"
+    color: isCouchMode ? "#0d0d14" : "transparent"
+    visibility: isCouchMode ? Window.FullScreen : Window.AutomaticVisibility
 
     Component.onCompleted: {
+        if (isCouchMode) {
             libraryView.restoreFocus()
+        } else {
+            if (App.config.windowWidth > 0) width = App.config.windowWidth
+            if (App.config.windowHeight > 0) height = App.config.windowHeight
+            if (App.config.windowMaximized) showMaximized()
+        }
+    }
+
+    onWidthChanged: {
+        if (!isCouchMode && visibility !== Window.Maximized && visibility !== Window.FullScreen)
+            App.config.setWindowSize(width, height)
+    }
+    onHeightChanged: {
+        if (!isCouchMode && visibility !== Window.Maximized && visibility !== Window.FullScreen)
+            App.config.setWindowSize(width, height)
+    }
+    onVisibilityChanged: {
+        if (!isCouchMode)
+            App.config.windowMaximized = (visibility === Window.Maximized)
     }
 
     Item {
         id: backdrop
         anchors.fill: parent
         z: 0
+        visible: isCouchMode
 
         Image {
             id: backdropImg
@@ -74,6 +97,7 @@ Maui.ApplicationWindow {
         anchors.fill: parent
         spacing: 0
         z: 1
+        visible: isCouchMode
 
         Rectangle {
             Layout.fillWidth: true
@@ -277,8 +301,17 @@ Maui.ApplicationWindow {
         id: gameEditDialog
     }
 
+    Loader {
+        id: desktopLoader
+        anchors.fill: parent
+        z: 1
+        active: !isCouchMode
+        source: "DesktopMain.qml"
+    }
+
     Connections {
         target: GamepadManager
+        enabled: isCouchMode
 
         function onBackPressed() {
             if (root.settingsVisible) { root.settingsVisible = false; return }