Function log_llm_response 

pub fn log_llm_response(
    datalog_dir: &Path,
    pending_request: Option<PathBuf>,
    text: &str,
    tool_calls: &[ToolCall],
    reasoning: &str,
    model: &str,
    step: usize,
    duration_ms: u64,
    enabled: bool,
)

Log the LLM response by merging it into the request file identified by pending_request. If pending_request is None (no prior request, or request write failed), writes a standalone *_orphan_response.json marked with a warning. Also appends a one-line summary to calls.log.

If enabled is false, this function is a no-op.