Add models and database persistence for protected phrase extraction

- Introduced dataclasses for phrase candidates, judgments, and matches in `models.py`.
- Implemented database operations for candidate and protected phrases in `store.py`, including loading, saving, and deleting phrases.
- Enhanced text normalization functions in `text_normalization.py` with detailed docstrings.
- Refactored search functionality to utilize new models and methods for detecting protected phrases.

python/ebook_search/api/routes/page.py

@@ -12,7 +12,7 @@ from python.ebook_search.api.dependencies import (
     AppConfig,  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
 )
 from python.ebook_search.api.web import templates
-from python.ebook_search.protected_phrases.lib import recalculate_candidate_phrases_for_book
+from python.ebook_search.protected_phrases.generate_ngrams import recalculate_candidate_phrases_for_book
 from python.fastapi_tools import DbSession  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
 from python.orm.richie import EbookCandidatePhrase, EbookProtectedPhrase, EbookSource