Typed primitive values for structured log fields. `LogParamValue` preserves type fidelity so that numbers remain numbers and booleans remain booleans in structured output (e.g. JSON), rather than everything being stringified.
data LogParamValue : TypeA primitive value that can appear in a structured log field.
StrVal : String -> LogParamValueIntVal : Integer -> LogParamValueFloatVal : Double -> LogParamValueBoolVal : Bool -> LogParamValueNullVal : LogParamValue