Use per-run branch name to avoid push collisions

Prior run pushed automation/sku-refresh-2026-04-24 successfully but
failed before opening the PR (issue-creation bug, now fixed). On the
next run, main has moved, so a new commit on the same branch name has
a different parent → non-fast-forward rejection.

Append ${{ github.run_number }} to make the branch unique per workflow
invocation. Orphan branches left behind can be cleaned up after their
PRs are merged/closed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitea/workflows/sku-catalog-refresh.yaml

@@ -84,7 +84,7 @@ jobs:
           GITEA_REPO: ${{ github.repository }}
         run: |
           DATE=$(date -u +%Y-%m-%d)
-          BRANCH="automation/sku-refresh-${DATE}"
+          BRANCH="automation/sku-refresh-${DATE}-run${{ github.run_number }}"
 
           git config user.name "sku-refresh-bot"
           git config user.email "sku-refresh@automation.local"