ci: use env vars for DRY workflow config (#6395)

.github/workflows/stale-issues.yml

@@ -5,6 +5,10 @@ on:
     - cron: "30 1 * * *" # Daily at 1:30 AM
   workflow_dispatch:
 
+env:
+  DAYS_BEFORE_STALE: 90
+  DAYS_BEFORE_CLOSE: 7
+
 jobs:
   stale:
     runs-on: ubuntu-latest
@@ -13,17 +17,17 @@ jobs:
     steps:
       - uses: actions/stale@v10
         with:
-          days-before-stale: 90
-          days-before-close: 7
+          days-before-stale: ${{ env.DAYS_BEFORE_STALE }}
+          days-before-close: ${{ env.DAYS_BEFORE_CLOSE }}
           stale-issue-label: "stale"
           close-issue-message: |
-            [automated] Closing due to 90+ days of inactivity.
+            [automated] Closing due to ${{ env.DAYS_BEFORE_STALE }}+ days of inactivity.
 
             Feel free to reopen if you still need this!
           stale-issue-message: |
-            [automated] This issue has had no activity for 90 days.
+            [automated] This issue has had no activity for ${{ env.DAYS_BEFORE_STALE }} days.
 
-            It will be closed in 7 days if there's no new activity.
+            It will be closed in ${{ env.DAYS_BEFORE_CLOSE }} days if there's no new activity.
           remove-stale-when-updated: true
           exempt-issue-labels: "pinned,security,feature-request,on-hold"
           start-date: "2025-12-27"