refactor(complexity): migrate tools_utility.py to class-based pattern (#1423)

* refactor(complexity): migrate tools_utility.py to class-based pattern

Extracts UtilityTools class from register_utility_tools closure, removing
the C901 suppression for this file from pyproject.toml.

- register_utility_tools (92) reduced to thin wrappers (~2)
- get_logs (20) reduced via _validate_log_level, _collect_log_warnings,
  _validate_log_slug, _fetch_log_source helpers
- _get_logbook (16) reduced via _coerce_logbook_params, _build_pagination_hint
- _get_logger_info (11) reduced via _parse_logger_entry static method
- _get_system_service_log (11) reduced via _addon_auth_error_suggestions static method
- slug type narrowed with assert in _fetch_log_source instead of type: ignore

* fix: resolve implicit string concatenation in _addon_auth_error_suggestions

Author: sergeykad

pyproject.toml

@@ -145,7 +145,6 @@ ignore = [
 "src/ha_mcp/tools/tools_entities.py" = ["C901"]
 "src/ha_mcp/tools/tools_registry.py" = ["C901"]
 "src/ha_mcp/tools/tools_search.py" = ["C901"]
-"src/ha_mcp/tools/tools_utility.py" = ["C901"]
 "src/ha_mcp/tools/smart_search.py" = ["C901"]
 
 [tool.pytest.ini_options]