What

Create a GitHub Actions workflow that automatically labels PRs based on the files they change.

Why

Manual labeling doesn't scale. Auto-labeling helps maintainers triage PRs faster and lets contributors see at a glance what domain a PR touches.

How

1. Create .github/workflows/pr-labeler.yml
2. Use actions/labeler@v5 (https://github.com/actions/labeler)
3. Create .github/labeler.yml with rules like:
   • src/*.cpp, src/*.h → code
   • docs/** → documentation
   • test/** → tests
   • .github/workflows/** → ci
   • data/lang/** → i18n
   • Dockerfile, docker-compose.yml → tools
4. Trigger on pull_request_target with types: [opened, synchronize]

References

• https://github.com/actions/labeler
• .github/workflows/build.yml — existing CI for syntax reference
• CONTRIBUTING.md — skill-to-issue mapping table (align labeler rules with these categories)

Acceptance

• .github/workflows/pr-labeler.yml created
• .github/labeler.yml with rules covering code, docs, tests, CI, i18n, and tools
• Workflow runs on PR open and sync
• Labels applied correctly when testing with a sample PR