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.

packages/nebula-ui/qml/Nebula/UI/NebulaIcon.qml

@@ -79,8 +79,11 @@ Item {
         case "document":
             paintDocument(ctx)
             break
+        case "application":
+            paintApplication(ctx)
+            break
         default:
-            paintFolder(ctx)
+            paintApplication(ctx)
             break
         }
     }
@@ -189,6 +192,23 @@ Item {
         ctx.stroke()
     }
 
+    function paintApplication(ctx) {
+        ctx.lineWidth = 1.5
+        ctx.beginPath()
+        roundedRect(ctx, 4.2, 5.2, 15.6, 13.6, 2.2)
+        ctx.stroke()
+        ctx.beginPath()
+        ctx.moveTo(4.2, 8.4)
+        ctx.lineTo(19.8, 8.4)
+        ctx.stroke()
+        ctx.beginPath()
+        ctx.arc(7, 6.8, 0.7, 0, Math.PI * 2)
+        ctx.fill()
+        ctx.beginPath()
+        ctx.arc(9.4, 6.8, 0.7, 0, Math.PI * 2)
+        ctx.fill()
+    }
+
     function paintFolder(ctx) {
         ctx.beginPath()
         ctx.moveTo(3.5, 8.2)