[chore] add stale action

.github/workflows/stale.yml

@@ -0,0 +1,31 @@
+name: "Close stale issues and pull requests"
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "12 5 * * *" # arbitrary time not to DDOS GitHub
+
+jobs:
+  stale:
+    runs-on: ubuntu-24.04
+    env:
+      GH_TOKEN: ${{ github.token }}
+    steps:
+      - name: Check rate_limit before
+        run: gh api /rate_limit
+      - uses: actions/stale@5bef64f19d7facfb25b37b414482c7164d639639 # v9.1.0
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          stale-pr-message: 'This PR was marked stale due to lack of activity. It will be closed in 14 days.'
+          close-pr-message: 'Closed as inactive. Feel free to reopen if this PR is still being worked on.'
+          close-issue-message: 'This issue has been closed as inactive because it has been stale for 120 days with no activity.'
+          close-issue-label: 'closed as inactive'
+          days-before-pr-stale: 14
+          days-before-issue-stale: 60
+          days-before-pr-close: 14
+          days-before-issue-close: 60
+          exempt-issue-labels: 'never stale,renovatebot'
+          ascending: true
+          operations-per-run: 6000
+          exempt-pr-labels: 'never stale,renovatebot'
+      - name: Check rate_limit after
+        run: gh api /rate_limit