Late chunking (the Jina single-pass technique) is a non-default embedding
path (chunking_strategy defaults to 'standard'). It adds a second full-document
forward pass with windowed token pooling for a marginal long-document gain that
the standard per-chunk encoder already covers at R@5 = 1.0 on the gold set.
- remove late_chunk_encode / _windowed_late_chunk_encode / _pool_spans /
_encode_tokens from embeddings.py (205 lines)
- remove the chunking_strategy == 'late' branch and _run_late_chunking from
ingestion.py (75 lines); 'late' now degrades to standard chunking
42 RAG tests pass.