telemetry method
Drain the runtime's telemetry ring buffer: recent on-device inference metrics, including per-fallback root-cause SyniFallbackDiagnostics.
Returns an empty list when the engine isn't loaded or nothing has been
recorded yet. The sensitive diagnostic fields (prompt / rawOutput) are
populated only when the runtime ran with capture_diagnostics enabled.
Implementation
Future<List<SyniInferenceMetric>> telemetry() async {
await initialize();
return parseTelemetry(await _worker!.telemetryJson());
}