The wrapped Error instance (never null; strings are coerced).
When true, the chart may be in an unusable state (e.g. initial history fetch failed). When false, the chart continues operating normally (e.g. a single dropped poll cycle).
Where in the chart pipeline the error originated.
Structured error payload dispatched by the chart. Replaces the previous silent
catch {}behavior so hosts can log, report to Sentry, or display a UI warning.