Promote shell to its own top-level directory

shell/plugins/notifications/manifest.json

@@ -0,0 +1,14 @@
+{
+  "schemaVersion": 1,
+  "id": "omarchy.notifications",
+  "name": "Notifications",
+  "version": "1.0.0",
+  "author": "Omarchy",
+  "description": "Notification daemon, popups, and history",
+  "kinds": ["service"],
+  "activation": "persistent",
+  "keepLoaded": true,
+  "entryPoints": {
+    "service": "Service.qml"
+  }
+}