ci: fix actions-timeline job placement for terminal accuracy

- superset-e2e.yml and superset-python-integrationtest.yml: include
  the "-required" gate jobs in actions-timeline's needs so the
  timeline snapshot waits for the true terminal jobs instead of
  racing them.
- superset-playwright.yml, pre-commit.yml, superset-extensions-cli.yml:
  move actions-timeline out of the matrixed job and into its own
  terminal job (needs: <matrix job>, if: always()) so matrix runs
  produce one timeline snapshot instead of one per matrix copy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/pre-commit.yml

@@ -33,10 +33,6 @@ jobs:
         # rarely differ across patch versions, so 3x per PR is wasteful.
         python-version: ${{ github.event_name == 'pull_request' && fromJSON('["current"]') || fromJSON('["current", "next"]') }}
     steps:
-      - uses: Kesin11/actions-timeline@7bf79990b7c09f5dfb570ac30b814ca597bd538e # v3.1.1
-        with:
-          expand-composite-actions: true
-
       - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
@@ -193,3 +189,12 @@ jobs:
             echo "📖 More details here: https://superset.apache.org/docs/contributing/development#git-hooks"
             exit 1
           fi
+
+  actions-timeline:
+    needs: pre-commit
+    if: always()
+    runs-on: ubuntu-26.04
+    steps:
+      - uses: Kesin11/actions-timeline@7bf79990b7c09f5dfb570ac30b814ca597bd538e # v3.1.1
+        with:
+          expand-composite-actions: true