Fix: unblock column_config E2E tests in CI

.github/workflows/playwright.yml

@@ -76,6 +76,14 @@ jobs:
           source venv/bin/activate
           pip install --upgrade pip
           pip install -r e2e_playwright/test-requirements.txt
+          # The venv is cached by a key that only changes daily, so a prior
+          # run's streamlit-pivot wheel is often already installed at the
+          # same version as the freshly-built wheel in dist/. When that
+          # happens, pip silently skips reinstalling ("Requirement already
+          # satisfied") and the test run exercises stale package code
+          # instead of the current checkout. Force-reinstall the local
+          # wheel (without deps) so the venv always reflects HEAD.
+          pip install --force-reinstall --no-deps dist/streamlit_pivot-*.whl
           python -m playwright install --with-deps
       - name: Run playwright tests
         run: |

e2e_playwright/pivot_table_column_config_app.py

@@ -27,12 +27,16 @@
 def render_app(data):
     df = data["df"]
 
+    # No col dims here so the single-value measure header (`pivot-header-cell`)
+    # renders and can be inspected by the measure label/help assertions. The
+    # col-dim + single-value layout does not surface a dedicated measure header
+    # (values fold into the grid cells), which would render the measure-level
+    # label/help assertions unreachable.
     st.subheader("column_config.label")
     st_pivot_table(
         df,
         key="test_pivot_cc_label",
         rows=["Region"],
-        columns=["Year"],
         values=["Revenue"],
         aggregation="sum",
         column_config={
@@ -48,7 +52,6 @@ def render_app(data):
         df,
         key="test_pivot_cc_help",
         rows=["Region"],
-        columns=["Year"],
         values=["Revenue"],
         aggregation="sum",
         column_config={