Add desktop app service and VM dev session tooling

Introduces a new `core/applications` QML/C++ module (`Nebula.Applications`) to discover `.desktop` entries, expose filterable application models, and launch installed apps safely from the shell. The desktop launcher now uses real installed apps with themed icon loading and fallback glyphs, adds output-aware surface sizing via `OutputTracker`, and wires in image/icon providers. It also adds VMware-focused Sway/shell wrapper scripts, updates Sway config/session env defaults, and refreshes README docs to document the new development flow and Desktop 0.1 behavior.

shells/desktop/shell/qml/components/AppItem.qml

@@ -11,6 +11,17 @@ Item {
     readonly property bool rowVariant: variant === "row"
     readonly property int iconSize: rowVariant ? 32 : (variant === "recent" ? 32 : 40)
     readonly property int glyphSize: rowVariant ? 16 : 18
+    readonly property string iconName: item && item.iconName ? item.iconName : ""
+    readonly property string fallbackGlyph: {
+        if (item && item.glyph)
+            return item.glyph
+        if (item && item.kind)
+            return item.kind
+        return "application"
+    }
+    readonly property url iconSource: iconName.length > 0
+        ? ("image://desktopicon/" + encodeURIComponent(iconName))
+        : ""
 
     implicitWidth: rowVariant ? parent ? parent.width : 200 : 90
     implicitHeight: rowVariant ? 48 : 78
@@ -54,9 +65,23 @@ Item {
                 border.width: 1
             }
 
+            Image {
+                id: tileIcon
+                anchors.centerIn: parent
+                width: root.iconSize - 8
+                height: root.iconSize - 8
+                fillMode: Image.PreserveAspectFit
+                asynchronous: true
+                smooth: true
+                cache: true
+                visible: status === Image.Ready
+                source: root.iconSource
+            }
+
             NebulaIcon {
                 anchors.centerIn: parent
-                name: item && item.glyph ? item.glyph : "folder"
+                visible: tileIcon.status !== Image.Ready
+                name: root.fallbackGlyph
                 size: root.glyphSize
                 color: item && item.tint ? item.tint : Theme.accent
             }
@@ -86,9 +111,23 @@ Item {
             anchors.verticalCenter: parent.verticalCenter
             color: Theme.iconWell
 
+            Image {
+                id: rowIcon
+                anchors.centerIn: parent
+                width: root.iconSize - 8
+                height: root.iconSize - 8
+                fillMode: Image.PreserveAspectFit
+                asynchronous: true
+                smooth: true
+                cache: true
+                visible: status === Image.Ready
+                source: root.iconSource
+            }
+
             NebulaIcon {
                 anchors.centerIn: parent
-                name: item && (item.glyph || item.kind) ? (item.glyph || item.kind) : "folder"
+                visible: rowIcon.status !== Image.Ready
+                name: root.fallbackGlyph
                 size: root.glyphSize
                 color: item && item.tint ? item.tint : Theme.accent
             }