fix: resolve positional config defaults without duplicate arguments

[林SO (Linxiushen)]

Passing None positionally to a method decorated with config_defaults raises TypeError: ... got multiple values for argument .... For example, both LLMCacheBase().set_api_cache(False, None) and OllamaClient(None, None) fail before the configured defaults can be used. The decorator adds a keyword argument while retaining the original positional argument.

Update the already-bound arguments and invoke the function using their positional and keyword views. This preserves positional-only parameters, variadic arguments, explicit overrides, and configuration changes between calls.

Validation uses actual cache objects and the Ollama constructor without network/model calls, plus parameter-binding controls:

• Baseline: 5 failed / 3 passed for the new regression tests.
• python -m pytest tests/unit/test_config_defaults.py tests/unit/test_api_cache.py::TestLLMCacheBase -q --tb=short -o addopts='': 14 passed (8 new regressions and 6 existing cache tests; Python 3.11, Windows).
• Two existing warnings concern the pytest timeout_exit option and a third-party Pydantic class configuration.

The full LLM-dependent core suite was not run.