complete performance and reliability follow-ups

packages/observability/src/trace.ts

@@ -1,4 +1,5 @@
 import { createTracer, type Context, type Middleware } from "@wrnexus/core";
+import { reportObservabilityFailure, type ObservabilityDiagnostic } from "./diagnostics.ts";
 
 export interface TraceContext {
   version: "00";
@@ -63,6 +64,7 @@ export interface TraceMiddlewareOptions {
   routeName?: (ctx: Context) => string;
   serverTiming?: boolean;
   onExportError?: (error: unknown, span: SpanRecord) => void | Promise<void>;
+  diagnostic?: ObservabilityDiagnostic;
 }
 
 export function traceMiddleware(options: TraceMiddlewareOptions = {}): Middleware {
@@ -131,7 +133,8 @@ export function traceMiddleware(options: TraceMiddlewareOptions = {}): Middlewar
           await options.onSpan?.(span);
           await options.exporter?.export([span]);
         } catch (error) {
-          await options.onExportError?.(error, span);
+          if (options.onExportError) await options.onExportError(error, span);
+          else reportObservabilityFailure("trace export failed", error, options.diagnostic);
         }
       }
     }