fix(webui): render local CLI image artifacts

webui/src/hooks/useNanobotStream.ts

@@ -193,6 +193,15 @@ function stampLastAssistantLatency(prev: UIMessage[], latencyMs: number): UIMess
   return prev;
 }
 
+function findLatestAssistantAnswerIndex(prev: UIMessage[]): number | null {
+  for (let i = prev.length - 1; i >= 0; i -= 1) {
+    const m = prev[i];
+    if (m.role === "assistant" && m.kind !== "trace") return i;
+    if (m.role === "user") break;
+  }
+  return null;
+}
+
 function absorbCompleteAssistantMessage(
   prev: UIMessage[],
   message: Omit<UIMessage, "id" | "role" | "createdAt">,
@@ -489,23 +498,41 @@ export function useNanobotStream(
     [appendAnswerChunk, ensureActivitySegmentId],
   );
 
-  const flushPendingStreamEvents = useCallback((options?: { closeAnswerSegment?: boolean }) => {
+  const flushPendingStreamEvents = useCallback((options?: {
+    closeAnswerSegment?: boolean;
+    finalAnswerText?: string;
+  }) => {
     if (streamFrameRef.current !== null) {
       window.cancelAnimationFrame(streamFrameRef.current);
       streamFrameRef.current = null;
     }
     const events = pendingStreamEventsRef.current;
-    if (events.length === 0) {
+    const finalAnswerText = options?.finalAnswerText;
+    if (events.length === 0 && finalAnswerText === undefined) {
       if (options?.closeAnswerSegment) closeActiveAssistantStream();
       return;
     }
     pendingStreamEventsRef.current = [];
     setMessages((prev) => {
-      const next = applyPendingStreamEvents(prev, events);
+      let next = events.length > 0 ? applyPendingStreamEvents(prev, events) : prev;
+      if (finalAnswerText !== undefined) {
+        const targetIndex =
+          resolveActiveAssistantIndex(next)
+          ?? findStreamingAssistantIndex(next, closedAssistantStreamIdsRef.current)
+          ?? findLatestAssistantAnswerIndex(next);
+        if (targetIndex !== null) {
+          const target = next[targetIndex];
+          next = replaceMessageAt(next, targetIndex, {
+            ...target,
+            content: finalAnswerText,
+            isStreaming: true,
+          });
+        }
+      }
       if (options?.closeAnswerSegment) closeActiveAssistantStream();
       return next;
     });
-  }, [applyPendingStreamEvents, closeActiveAssistantStream]);
+  }, [applyPendingStreamEvents, closeActiveAssistantStream, resolveActiveAssistantIndex]);
 
   const schedulePendingStreamFlush = useCallback(() => {
     if (streamFrameRef.current !== null) return;
@@ -583,7 +610,10 @@ export function useNanobotStream(
       }
 
       if (ev.event === "stream_end") {
-        flushPendingStreamEvents({ closeAnswerSegment: true });
+        flushPendingStreamEvents({
+          closeAnswerSegment: true,
+          ...(typeof ev.text === "string" ? { finalAnswerText: ev.text } : {}),
+        });
         if (suppressStreamUntilTurnEndRef.current) return;
         // stream_end only means the text segment finished — the model may
         // still be executing tools.  Do NOT reset isStreaming here; the