Document the implementation and verification of the test-matrix DAG
branch with musl and glibc test legs.
Summary:
- Created pdftract-test-image-build WorkflowTemplate
- Verified test-matrix DAG implementation (test-glibc, test-musl)
- Both legs emit JUnit XML for test reporting
- Acceptance criteria: PASS (with notes on setup step and Docker image)
Known dependencies:
- Setup step still a placeholder (handled by separate Phase 0 bead)
- Docker image needs to be built via pdftract-test-image-build workflow
Relates to pdftract-30n: Phase 0.3 Test execution — cargo test on musl + glibc
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Bead-Id: pdftract-30n
