The llamacpp() provider connects tidyllm to a locally running
llama.cpp server. It exposes
the same verb/provider pattern as every other tidyllm provider while
also offering llama.cpp-specific features: BNF grammar constraints
(.grammar), token logprobs (.logprobs), and model management helpers.
The server must be started separately before calling llamacpp(). See
llamacpp_health() to verify the server is running, and
llamacpp_download_model() / list_hf_gguf_files() to obtain models.
Value
The result of the requested action (e.g., an updated LLMMessage
for chat(), a tibble for embed() or list_models()).
