ci: bump GitHub Actions to latest major versions

actions/checkout and other pinned actions had drifted behind their
latest published major version, triggering Node.js deprecation warnings
in CI logs.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: jnasbyupgrade

.github/workflows/claude-code-review.yml

@@ -78,7 +78,7 @@ jobs:
         if: steps.gate.outputs.decision == 'run'
         # Intentionally tracks the major-version tag (not a pinned SHA) so
         # upstream fixes are picked up automatically.
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
         with:
           repository: ${{ github.event.pull_request.head.repo.full_name }}
           ref: ${{ github.event.pull_request.head.sha }}

.github/workflows/claude.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Checkout repository
         # Intentionally tracks the major-version tag (not a pinned SHA) so
         # upstream fixes are picked up automatically.
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
         with:
           fetch-depth: 1
           persist-credentials: false