GitHub: Replace workflow with reusable workflow from org

Pull Request: https://projects.blender.org/blender/blender/pulls/153593

.github/workflows/close-prs.yml

@@ -0,0 +1,11 @@
+name: Close GitHub Pull Requests
+
+on:
+  schedule:
+    - cron: '* */12 * * *'
+
+jobs:
+  close_prs:
+    uses: blender/.github/.github/workflows/close-github-prs.yml@main
+    with:
+      allowed-repo: blender/blender

.github/workflows/stale.yml

@@ -1,32 +0,0 @@
-# GitHub Actions workflow for automatically closing pull requests
-# This workflow is specific to Blender's GitHub mirror and directs contributors to the official development platform on blender.org
-
-name: Close GitHub Pull Requests
-
-# Trigger this workflow every 12 hours.
-on:
-  schedule:
-    - cron: '* */12 * * *'
-
-jobs:
-  close_prs:
-    name: Close Pull Requests
-    runs-on: ubuntu-latest
-    # Only run this job in the read-only mirror repository.
-    if: github.repository == 'blender/blender' && contains(github.server_url, 'github.com')
-    # Permissions granted to the GitHub Actions bot.
-    permissions:
-      pull-requests: write
-    steps:
-      - uses: actions/stale@v9
-        with:
-          # Number of days before a pull request is marked as stale.
-          days-before-pr-stale: 0
-          # Number of days before a pull request is closed.
-          days-before-pr-close: 0
-          # Message posted when closing a pull request.
-          stale-pr-message: |
-            This pull request has been automatically closed because this repository is a read-only mirror. Blender development happens on [projects.blender.org](https://projects.blender.org).
-
-            To contribute code, please read:
-            https://developer.blender.org/docs/handbook/contributing/