fix: retain authentication diagnostics across empty stream blocks

docker/gateguard-effectiveness/lib.js

@@ -308,7 +308,7 @@ function runTrial(trial, { workRoot, armSettingsByName, executable, model, maxTu
     providerMessage: stream.result && stream.result.is_error === true
       ? String(stream.result.result || '').slice(0, 200)
       : !stream.result
-        ? String(stream.texts[stream.texts.length - 1] || '').slice(0, 200) || null
+        ? String([...stream.texts].reverse().find(text => text.trim() !== '') || '').slice(0, 200) || null
         : null,
     wallMs: Date.now() - started,
     passed: outcome.passed,

docker/gateguard-effectiveness/session.js

@@ -115,7 +115,8 @@ function runConversation({ cwd, stateDir, settingsPath, prompt, intent }, option
     // conversation rather than being graded as a finding.
     if (!stream.result || stream.result.is_error === true) {
       providerError = true;
-      providerMessage = String((stream.result && stream.result.result) || finalText(stream) || '').slice(0, 200) || null;
+      providerMessage = String((stream.result && stream.result.result)
+        || [...stream.texts].reverse().find(text => text.trim() !== '') || '').slice(0, 200) || null;
     }
     addUsage(usage, stream.result);
     denialsPerTurn.push(stream.gateDenials);