Implement MVC design and lazy loading (aiidalab#802)

This is a large-scale redesign that focuses on the separation of data/business logic from the UI. Data is contained in `Model` classes as `traitlets` traits, which are observed in the `Controller`/`View` widgets and handled by `Controller` event handlers. `Controller`s also observe changes in their respective `View`s to handle user events. The design relies predominantly on the Observer pattern, with a few exceptions handled as a Mediator pattern.

Lazy loading is implemented via `render` methods triggered when the user visits the relevant component. However, the `Model` network is decoupled from the UI and remains in sync as a source of truth. `View`s sync up with the `Model` network on render.

Some changes in the UI were included here to better fit with the MVC design and the principles of lazy loading. Clear documentation will be provided in a follow-up PR.

.github/workflows/ci.yml

@@ -55,7 +55,7 @@ jobs:
               # Only collect code coverage with aiida-core=2.3, to speed up tests
               # with higher aiida versions that for some reason run slower, see:
               # https://github.com/aiidalab/aiidalab-qe/issues/766
-              run: pytest -v tests ${{ matrix.aiida-core-version == '2.3' && '--cov=aiidalab_qe' || '' }}
+              run: pytest -v tests ${{ matrix.aiida-core-version == '2.3' && '--cov=aiidalab_qe' || '' }} --skip-slow
 
             - name: Upload coverage reports to Codecov
               uses: codecov/codecov-action@v4

qe.ipynb

@@ -73,8 +73,6 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "import urllib.parse as urlparse\n",
-    "\n",
     "from aiidalab_qe.app.main import App\n",
     "from aiidalab_widgets_base.bug_report import (\n",
     "    install_create_github_issue_exception_handler,\n",
@@ -86,17 +84,23 @@
     "    labels=(\"bug\", \"automated-report\"),\n",
     ")\n",
     "\n",
+    "app = App(qe_auto_setup=True)\n",
+    "\n",
+    "view.main.children = [app]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import urllib.parse as urlparse\n",
+    "\n",
     "url = urlparse.urlsplit(jupyter_notebook_url)  # noqa F821\n",
     "query = urlparse.parse_qs(url.query)\n",
-    "\n",
-    "app = App(qe_auto_setup=True)\n",
-    "# if a pk is provided in the query string, set it as the process of the app\n",
     "if \"pk\" in query:\n",
-    "    pk = query[\"pk\"][0]\n",
-    "    app.process = pk\n",
-    "\n",
-    "view.main.children = [app]\n",
-    "view.app = app"
+    "    app.process = query[\"pk\"][0]"
    ]
   },
   {
@@ -111,7 +115,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3 (ipykernel)",
+   "display_name": "base",
    "language": "python",
    "name": "python3"
   },
@@ -126,11 +130,6 @@
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
    "version": "3.9.13"
-  },
-  "vscode": {
-   "interpreter": {
-    "hash": "d4d1e4263499bec80672ea0156c357c1ee493ec2b1c70f0acce89fc37c4a6abe"
-   }
   }
  },
  "nbformat": 4,

setup.cfg

@@ -57,8 +57,8 @@ aiidalab_qe.plugins.xas = pseudo_toc.yaml
 aiidalab_qe.properties =
     bands = aiidalab_qe.plugins.bands:bands
     pdos = aiidalab_qe.plugins.pdos:pdos
-    xps = aiidalab_qe.plugins.xps:xps
     electronic_structure = aiidalab_qe.plugins.electronic_structure:electronic_structure
+    xps = aiidalab_qe.plugins.xps:xps
     xas = aiidalab_qe.plugins.xas:xas
 
 aiida.workflows =