Fix marimo Playwright tests by displaying widgets as cell output (#531)

Widget cells used assignment statements as their last expression, but
marimo only renders bare expressions as cell output. Adding the widget
variable as a bare expression causes marimo to actually display the
anywidget in the browser, which the Playwright tests depend on.

Also removes continue-on-error and timeout-minutes from TestMarimo CI
job now that the tests pass.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: paddymul

.github/workflows/ci.yml

@@ -240,8 +240,6 @@ jobs:
     name: Marimo Playwright Tests
     needs: [BuildWheel]
     runs-on: depot-ubuntu-latest
-    timeout-minutes: 4
-    continue-on-error: true
     steps:
       - uses: actions/checkout@v4
       - name: Install uv

tests/notebooks/marimo_pw_test.py

@@ -32,6 +32,7 @@ def _(BuckarooWidget, pd):
         'score': [88.5, 92.3, 76.1, 95.0, 81.7],
     })
     small_widget = BuckarooWidget(small_df)
+    small_widget
     return small_df, small_widget
 
 
@@ -48,6 +49,7 @@ def _(BuckarooInfiniteWidget, pd):
         rows.append({'id': i, 'value': i * 10, 'label': f'row_{i}'})
     large_df = pd.DataFrame(rows)
     large_widget = BuckarooInfiniteWidget(large_df)
+    large_widget
     return large_df, rows, large_widget