feat: native provider passthrough with key injection and best-effort accounting

registry_test.go

@@ -40,6 +40,7 @@ func (f *fakeAdapter) listModels(ctx context.Context) ([]string, error) {
 	}
 	return f.listModelsFn(ctx)
 }
+func (f *fakeAdapter) httpClient() *http.Client { return nil }
 
 // recordingLog is a thread-safe log func for tests, capturing formatted
 // lines instead of writing to stderr.