fix(ci): restore main-style all-required sentinel

During staging→main merge conflict resolution the all-required job
accidentally inherited staging's  +  +
shape while keeping main's Python polling script. This creates a broken
hybrid: the job is killed after 1 minute before the 40-minute polling
deadline, and  +  re-introduces the Gitea 1.22
skipped-sentinel bug that main deliberately avoids.

Restore main's proven shape: no , no ,
, Python polling.

Per core-devops review on PR #1242.

.gitea/workflows/ci.yml

@@ -564,14 +564,7 @@ jobs:
     #
     continue-on-error: false
     runs-on: ubuntu-latest
-    timeout-minutes: 1
-    needs:
-      - changes
-      - platform-build
-      - canvas-build
-      - shellcheck
-      - python-lint
-    if: ${{ always() }}
+    timeout-minutes: 45
     steps:
       - name: Wait for required CI contexts
         env: