Fix all test type errors and enable ty check on tests

- Fix test_basic.py: search() takes str not list
- Fix test_cli_prompt_template.py: add type: ignore for Mock assignments
- Fix test_prompt_template_persistence.py: match BaseSearcher.search signature
- Fix test_prompt_template_e2e.py: add type narrowing asserts after skip
- Fix test_readme_examples.py: use explicit kwargs instead of **model_args
- Fix metadata_filter.py: allow Optional[MetadataFilters]
- Update CI to run ty check on tests

packages/leann-core/src/leann/metadata_filter.py

@@ -7,7 +7,7 @@ operators for different data types including numbers, strings, booleans, and lis
 """
 
 import logging
-from typing import Any, Union
+from typing import Any, Optional, Union
 
 logger = logging.getLogger(__name__)
 
@@ -47,7 +47,7 @@ class MetadataFilterEngine:
         }
 
     def apply_filters(
-        self, search_results: list[dict[str, Any]], metadata_filters: MetadataFilters
+        self, search_results: list[dict[str, Any]], metadata_filters: Optional[MetadataFilters]
     ) -> list[dict[str, Any]]:
         """
         Apply metadata filters to a list of search results.