* fix: recover embedding after transient health failure
* refactor(embedding_store): remove provider_success_count and simplify health recovery logic
- Deleted provider_success_count attribute and related methods across embedding and file stores
- Updated _recover_after_real_request to rely solely on is_healthy flag for recovery decisions
- Removed redundant counting logic for provider successes during embedding operations
- Cleaned up health status management to streamline provider recovery detection
- Adjusted unit tests to align with removal of provider_success_count and maintain health checks consistency
* refactor(embedding_store): use default health check timeout
* fix(embedding_store): ensure is_healthy remains unchanged on cache hits
- Updated get_embeddings docstring to clarify cache hits must not alter is_healthy state
- Improved code comment for embedding dimension matching method
* fix(file_store): make embedding recovery race-safe
* ci: use default CodeQL query suite
* fix(file_store): preserve queued embedding rebuilds
* fix(file_store): preserve verified recovery without chunks
