Add workflow to manage stale pull requests

.github/workflows/stale_pr_close.yml

@@ -0,0 +1,89 @@
+name: Stale PR Management
+
+on:
+  schedule:
+    # Runs daily at midnight UTC
+    - cron: "0 0 * * *"
+  pull_request:
+    types:
+      - labeled
+
+jobs:
+  stale-prs:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Handle stale label
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const now = new Date();
+            const owner = context.repo.owner;
+            const repo = context.repo.repo;
+
+            // Handle when PR is labeled
+            if (context.eventName === "pull_request" && context.payload.action === "labeled") {
+              const label = context.payload.label?.name;
+              if (label === "stale") {
+                await github.issues.createComment({
+                  owner,
+                  repo,
+                  issue_number: context.payload.pull_request.number,
+                  body: "This PR has been marked as stale. It will be closed if no new commits are added in 7 days."
+                });
+              }
+              return;
+            }
+
+            // Scheduled run: fetch all open PRs
+            const { data: prs } = await github.pulls.list({
+              owner,
+              repo,
+              state: "open",
+              per_page: 100
+            });
+
+            for (const pr of prs) {
+              const hasStale = pr.labels.some(l => l.name === "stale");
+              if (!hasStale) continue;
+
+              // Fetch commits for this PR
+              const { data: commits } = await github.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) {
+                // Close stale PR
+                await github.pulls.update({
+                  owner,
+                  repo,
+                  pull_number: pr.number,
+                  state: "closed"
+                });
+                await github.issues.createComment({
+                  owner,
+                  repo,
+                  issue_number: pr.number,
+                  body: "Closing stale PR due to inactivity."
+                });
+              } else if (lastCommitDate > new Date(now - 7*24*60*60*1000)) {
+                // Remove stale label if recent activity
+                await github.issues.removeLabel({
+                  owner,
+                  repo,
+                  issue_number: pr.number,
+                  name: "stale"
+                });
+                await github.issues.createComment({
+                  owner,
+                  repo,
+                  issue_number: pr.number,
+                  body: "Recent activity detected. Removing stale label."
+                });
+              }
+            }