ci: retrigger checks now that labels are attached

Labels are added via a separate API call after PR creation, which fires a
`labeled` event that .github/workflows/check.yml doesn't listen for (only
opened/synchronize/reopened). Without a new push, the host/Apple/Android
jobs gated on those labels would never actually run against this PR. This
empty commit forces a `synchronize` event so they do.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DaK9eAAF5G8wj6UT8VekAm

Author: claude