ci: fix stale issue progress and increase processing budget

Grant cache write access so stale processing can save progress across runs.
Raise the operation budget to 1000 to cover the current backlog in one run.
Retain the policy of 60 inactive days before marking stale and 14 additional
days before closure.

.github/workflows/stale.yml

@@ -6,6 +6,7 @@ on:
   workflow_dispatch:
 
 permissions:
+  actions: write
   issues: write
   pull-requests: read
 
@@ -17,6 +18,7 @@ jobs:
     steps:
       - uses: actions/stale@4391f3da665fdf50b6810c1a66712fb9ba21aa93 # v11.0.0
         with:
+          operations-per-run: 1000
           days-before-issue-stale: 60
           days-before-issue-close: 14
           days-before-pr-stale: -1