refactor(ebook-search): simplify search and phrase matching

tests/ebook_search/test_rag_pipeline.py

@@ -62,8 +62,9 @@ async def test_search_ebooks_runs_phrase_detection_in_parallel_with_retrieval(mo
         assert await asyncio.to_thread(phrase_started.wait, 2)
         return [SearchResult(chunk_id=1, text="vector", source_title="Vector", vector_score=0.9)]
 
-    async def fake_query_phrase_matches(_engine, _query, _config):
+    async def fake_query_phrase_matches(_engine, _query, _config, *, phrase_matching):
         """Record that phrase detection started and return no matches."""
+        assert phrase_matching is True
         phrase_started.set()
         return []
 
@@ -90,7 +91,7 @@ async def test_search_ebooks_skips_phrase_matching_when_disabled(mocker: MockerF
         return_value=[SearchResult(chunk_id=1, text="vector", source_title="Vector", vector_score=0.9)],
     )
     mocker.patch("python.ebook_search.search.bm25_candidates", return_value=[])
-    detect_mock = mocker.patch("python.ebook_search.search.query_phrase_matches")
+    detect_mock = mocker.patch("python.ebook_search.search.detect_protected_phrases_for_query")
     boost_mock = mocker.patch("python.ebook_search.search.apply_phrase_mention_boosts")
     config = EbookSearchConfig(rerank=RerankConfig(enabled=False))
 
@@ -115,7 +116,7 @@ async def test_search_ebooks_ignores_phrase_matching_when_config_disabled(mocker
         return_value=[SearchResult(chunk_id=1, text="vector", source_title="Vector", vector_score=0.9)],
     )
     mocker.patch("python.ebook_search.search.bm25_candidates", return_value=[])
-    detect_mock = mocker.patch("python.ebook_search.search.query_phrase_matches")
+    detect_mock = mocker.patch("python.ebook_search.search.detect_protected_phrases_for_query")
     boost_mock = mocker.patch("python.ebook_search.search.apply_phrase_mention_boosts")
     config = EbookSearchConfig(rerank=RerankConfig(enabled=False), phrase_matching_enabled=False)