fix: NameError 'has_reranker' in e2e-rag single-shot result display

[Anai-Guo]

Problem

evaluate_retrieval_query() in e2e-rag/evaluation.py references an undefined
name has_reranker when displaying results:

# Show reranked results if reranker is available and reranking was used
if not no_rerank and has_reranker:   # <-- has_reranker is never defined

has_reranker is not defined anywhere in the function. This branch is guarded by
if print_results:, and single_shot_retrieval.py calls the function with
print_results=True and the default no_rerank=False:

eval_output = evaluate_retrieval_query(
    rag_db, args.query, expected_urls=[],
    ...
    no_rerank=getattr(args, 'no_rerank', False),
    ...
    print_results=True,
    ...
)

So any single-query lookup that runs with reranking enabled raises
NameError: name 'has_reranker' is not defined right where it should be printing
the reranked results.

Fix

Reuse the exact reranker-availability check the same function already performs
earlier (Step 2, ~line 144):

if not no_rerank and hasattr(rag_db, '_reranker_model') and rag_db._reranker_model is not None:

One-line change, no behavior change beyond removing the crash.

🤖 Generated with Claude Code

[github-actions]

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