Add two PDF/A fixtures for testing assisted-OCR (BrokenVector path):
- Aligned fixture with correctly-positioned invisible text layer
- Misaligned fixture with text layer offset by (10pt, 5pt)
Extend ci/wer-gate.sh with WER validation for BrokenVector fixtures.
Acceptance criteria:
- Two BrokenVector fixtures committed (both 1.5 KB, well under 200 KB limit)
- ci/wer-gate.sh extended with new fixture invocations
- WER delta tests will skip gracefully when OCR environment unavailable
Closes: pdftract-48ea
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
