chore: Remove stale action

.forgejo/workflows/stale.yml

@@ -1,17 +0,0 @@
-name: Stale PR Cleanup
-
-on:
-  workflow_dispatch:
-  schedule:
-    - cron: "@hourly"
-
-jobs:
-  stale:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/stale@v9
-        with:
-          repo-token: "${{ secrets.GITHUB_TOKEN }}"
-          days-before-stale: 7
-          stale-pr-message: "This PR will be closed in 7 days due to inactivity. Add a comment or remove the 'Stale' label to keep it open."
-          days-before-issue-stale: -1