LLM observability — capture a model invocation as a trace span.
Wraps POST /llm/trace. The wire payload is camelCase (matching the edge
function's Zod schema) and authenticates with X-BillDog-API-Key.
Mirrors the Node SDK llm.ts.
Summary
Functions
Record a single LLM trace span.
Functions
@spec capture_trace( BilldogEng.t(), keyword() ) :: {:ok, term()} | {:error, BilldogEng.Error.t()}
Record a single LLM trace span.
Required params (keyword list): :trace_id, :span_id, :model,
:input_text, :output_text.
Optional: :parent_span_id, :prompt_tokens, :completion_tokens,
:duration_ms, :cost_usd, :properties, :metadata, :timestamp
(ISO-8601; defaults to now).