Add test_data.py (cocotb Python module) and test_vectors.h (C header)
with 20 test vectors from the Python behavioral model. LLR data is
packed 5 per 32-bit word matching the wishbone interface format.
11 converged vectors for positive testing, 9 non-converged for
negative testing.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
