Refactor stale PR close workflow permissions and script

.github/workflows/stale_pr_close.yml

@@ -9,22 +9,15 @@ on:
 jobs:
   stale-prs:
     runs-on: ubuntu-latest
-    permissions:
-      pull-requests: write
-      issues: write
     steps:
       - name: Handle stale label
         uses: actions/github-script@v7
         with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
-            console.log('github object:', typeof github);
-            console.log('github.rest:', typeof github?.rest);
-            console.log('context.eventName:', context.eventName);
-            
             const now = new Date();
             const owner = context.repo.owner;
             const repo = context.repo.repo;
-            
             // --- PR labeled event ---
             if (context.eventName === "pull_request" && context.payload.action === "labeled") {
               const label = context.payload.label?.name;
@@ -38,7 +31,6 @@ jobs:
               }
               return; // exit, nothing else to do
             }
-            
             // --- Scheduled run ---
             const { data: prs } = await github.rest.pulls.list({
               owner,
@@ -46,20 +38,16 @@ jobs:
               state: "open",
               per_page: 100
             });
-            
             for (const pr of prs) {
               const hasStale = pr.labels.some(l => l.name === "stale");
               if (!hasStale) continue;
-              
               const { data: commits } = await github.rest.pulls.listCommits({
                 owner,
                 repo,
                 pull_number: pr.number
               });
-              
               const lastCommitDate = new Date(commits[commits.length - 1].commit.author.date);
               const diffDays = (now - lastCommitDate) / (1000 * 60 * 60 * 24);
-              
               if (diffDays > 7) {
                 await github.rest.pulls.update({
                   owner,