fix(ci): restore broken YAML structure in 3 workflows, revert aggressive STALE_HOURS

- pr-auto-response.yml: restore permissions, steps, and checkout in
  contributor-tier-issues job (broken by runner swap)
- pr-check-stale.yml: restore steps block and step name
- pr-intake-checks.yml: restore steps block, checkout, and timeout
- pr-check-status.yml: revert STALE_HOURS from 4 to 48 (not a cost
  optimization; 4h is too aggressive), switch to ubuntu-latest per
  PR description

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/workflows/pr-auto-response.yml

@@ -16,6 +16,15 @@ jobs:
       (github.event_name == 'pull_request_target' &&
       (github.event.action == 'labeled' || github.event.action == 'unlabeled'))
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      issues: write
+      pull-requests: write
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+
+      - name: Apply contributor tier label for issue author
         uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
         env:
           LABEL_POLICY_PATH: .github/label-policy.json

.github/workflows/pr-check-stale.yml

@@ -13,6 +13,8 @@ jobs:
             issues: write
             pull-requests: write
         runs-on: ubuntu-latest
+        steps:
+            - name: Mark stale issues and pull requests
               uses: actions/stale@b5d41d4e1d5dceea10e7104786b73624c18a190f # v10.2.0
               with:
                   repo-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/pr-check-status.yml

@@ -13,13 +13,13 @@ concurrency:
 
 jobs:
   nudge-stale-prs:
-    runs-on: blacksmith-2vcpu-ubuntu-2404
+    runs-on: ubuntu-latest
     permissions:
       contents: read
       pull-requests: write
       issues: write
     env:
-      STALE_HOURS: "4"
+      STALE_HOURS: "48"
     steps:
       - name: Checkout repository
         uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4

.github/workflows/pr-intake-checks.yml

@@ -17,6 +17,12 @@ jobs:
     intake:
         name: Intake Checks
         runs-on: ubuntu-latest
+        timeout-minutes: 10
+        steps:
+            - name: Checkout repository
+              uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+
+            - name: Run safe PR intake checks
               uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
               with:
                   script: |