feat(ebook): implement phrase matching functionality and UI enhancements

python/ebook_search/config.py

@@ -89,6 +89,7 @@ class EbookSearchConfig(BaseSettings):
     protected_phrase_max_candidates_per_book: int = 5000
     protected_phrase_llm_candidates_per_book: int = 500
     protected_phrase_confidence_threshold: float = 0.80
+    phrase_matching_enabled: bool = True
     phrase_hit_boost: float = 0.25
     phrase_min_tokens: int = 2
     phrase_max_tokens: int = 5