chore(ci): remove stale issue and pull request automation (#6133)

Remove the aggressive 14-day stale and 3-day close policy so valid issues and contributions are not discarded during maintainer review delays.

.github/workflows/stale.yml

@@ -1,24 +0,0 @@
-name: Close Stale
-
-on:
-  schedule:
-    - cron: "0 */8 * * *" # Every 8 hours
-
-jobs:
-  close-stale:
-    name: Close Stale Issues and PRs
-    runs-on: ubuntu-latest
-    permissions:
-      issues: write
-      pull-requests: write
-    steps:
-      - name: Mark and close stale issues and PRs
-        uses: actions/stale@v10.1.1
-        with:
-          # Issues: mark stale after 14 days of inactivity, close after 3 more days
-          days-before-issue-stale: 14
-          days-before-issue-close: 3
-
-          # Pull requests: mark stale after 14 days of inactivity, close after 3 more days
-          days-before-pr-stale: 14
-          days-before-pr-close: 3