Update GitHub Actions to latest major versions (#36964)

Update all Actions to their latest major versions:

- `actions/checkout`: v5 → v6
- `dorny/paths-filter`: v3 → v4
- `pnpm/action-setup`: v4 → v5
- `docker/setup-qemu-action`: v3 → v4
- `docker/setup-buildx-action`: v3 → v4
- `docker/build-push-action`: v6 → v7
- `docker/metadata-action`: v5 → v6
- `docker/login-action`: v3 → v4
- `crazy-max/ghaction-import-gpg`: v6 → v7
- `aws-actions/configure-aws-credentials`: v5 → v6

All updates are Node 24 runtime bumps with no workflow-breaking changes
for our usage.

Co-authored-by: Claude (Opus 4.6) <noreply@anthropic.com>

.github/workflows/files-changed.yml

@@ -40,7 +40,7 @@ jobs:
       json: ${{ steps.changes.outputs.json }}
     steps:
       - uses: actions/checkout@v6
-      - uses: dorny/paths-filter@v3
+      - uses: dorny/paths-filter@v4
         id: changes
         with:
           filters: |