fix(rebase): restore FeedbackButtons component and enrichment lost during rebase

The FeedbackButtons component (defined inline in message-list-item.tsx)
was introduced in commit 95df8d13 but lost during rebase. The previous
rebase cleanup commit incorrectly removed the feedback/runId props and
enrichment hook as "orphaned code" instead of restoring the missing
component. This commit restores:

- FeedbackButtons component with thumbs up/down toggle and optimistic state
- FeedbackData/upsertFeedback/deleteFeedback imports
- feedback and runId props on MessageListItem
- useThreadMessageEnrichment hook and entry lookup in message-list.tsx

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/workspace/messages/message-list-item.tsx

@@ -1,6 +1,6 @@
 import type { Message } from "@langchain/langgraph-sdk";
-import { FileIcon, Loader2Icon } from "lucide-react";
-import { memo, useMemo, type ImgHTMLAttributes } from "react";
+import { FileIcon, Loader2Icon, ThumbsDownIcon, ThumbsUpIcon } from "lucide-react";
+import { memo, useCallback, useMemo, useState, type ImgHTMLAttributes } from "react";
 import rehypeKatex from "rehype-katex";
 
 import { Loader } from "@/components/ai-elements/loader";
@@ -17,6 +17,11 @@ import {
 } from "@/components/ai-elements/reasoning";
 import { Task, TaskTrigger } from "@/components/ai-elements/task";
 import { Badge } from "@/components/ui/badge";
+import {
+  deleteFeedback,
+  upsertFeedback,
+  type FeedbackData,
+} from "@/core/api/feedback";
 import { resolveArtifactURL } from "@/core/artifacts/utils";
 import { useI18n } from "@/core/i18n/hooks";
 import {
@@ -34,16 +39,85 @@ import { CopyButton } from "../copy-button";
 
 import { MarkdownContent } from "./markdown-content";
 
+function FeedbackButtons({
+  threadId,
+  runId,
+  initialFeedback,
+}: {
+  threadId: string;
+  runId: string;
+  initialFeedback: FeedbackData | null;
+}) {
+  const [feedback, setFeedback] = useState<FeedbackData | null>(initialFeedback);
+  const [isSubmitting, setIsSubmitting] = useState(false);
+
+  const handleClick = useCallback(
+    async (rating: number) => {
+      if (isSubmitting) return;
+      setIsSubmitting(true);
+      try {
+        if (feedback?.rating === rating) {
+          await deleteFeedback(threadId, runId);
+          setFeedback(null);
+        } else {
+          const result = await upsertFeedback(threadId, runId, rating);
+          setFeedback(result);
+        }
+      } catch {
+        // Revert on error — feedback state unchanged on catch
+      } finally {
+        setIsSubmitting(false);
+      }
+    },
+    [threadId, runId, feedback, isSubmitting],
+  );
+
+  return (
+    <div className="flex gap-1">
+      <button
+        type="button"
+        className={cn(
+          "text-muted-foreground hover:text-foreground rounded-md p-1 transition-colors",
+          feedback?.rating === 1 && "text-foreground",
+        )}
+        onClick={() => handleClick(1)}
+        disabled={isSubmitting}
+      >
+        <ThumbsUpIcon
+          className={cn("size-4", feedback?.rating === 1 && "fill-current")}
+        />
+      </button>
+      <button
+        type="button"
+        className={cn(
+          "text-muted-foreground hover:text-foreground rounded-md p-1 transition-colors",
+          feedback?.rating === -1 && "text-foreground",
+        )}
+        onClick={() => handleClick(-1)}
+        disabled={isSubmitting}
+      >
+        <ThumbsDownIcon
+          className={cn("size-4", feedback?.rating === -1 && "fill-current")}
+        />
+      </button>
+    </div>
+  );
+}
+
 export function MessageListItem({
   className,
   threadId,
   message,
   isLoading,
+  feedback,
+  runId,
 }: {
   className?: string;
   threadId: string;
   message: Message;
   isLoading?: boolean;
+  feedback?: FeedbackData | null;
+  runId?: string;
 }) {
   const isHuman = message.type === "human";
   return (
@@ -72,6 +146,13 @@ export function MessageListItem({
                 ""
               }
             />
+            {feedback !== undefined && runId && threadId && (
+              <FeedbackButtons
+                threadId={threadId}
+                runId={runId}
+                initialFeedback={feedback}
+              />
+            )}
           </div>
         </MessageToolbar>
       )}

frontend/src/components/workspace/messages/message-list.tsx

@@ -18,6 +18,7 @@ import { useRehypeSplitWordsIntoSpans } from "@/core/rehype";
 import type { Subtask } from "@/core/tasks";
 import { useUpdateSubtask } from "@/core/tasks/context";
 import type { AgentThreadState } from "@/core/threads";
+import { useThreadMessageEnrichment } from "@/core/threads/hooks";
 import { cn } from "@/lib/utils";
 
 import { ArtifactFileList } from "../artifacts/artifact-file-list";
@@ -47,6 +48,7 @@ export function MessageList({
   const rehypePlugins = useRehypeSplitWordsIntoSpans(thread.isLoading);
   const updateSubtask = useUpdateSubtask();
   const messages = thread.messages;
+  const { data: enrichment } = useThreadMessageEnrichment(threadId);
 
   if (thread.isThreadLoading && messages.length === 0) {
     return <MessageListSkeleton />;
@@ -59,12 +61,15 @@ export function MessageList({
         {groupMessages(messages, (group) => {
           if (group.type === "human" || group.type === "assistant") {
             return group.messages.map((msg) => {
+              const entry = msg.id ? enrichment?.get(msg.id) : undefined;
               return (
                 <MessageListItem
                   key={`${group.id}/${msg.id}`}
                   threadId={threadId}
                   message={msg}
                   isLoading={thread.isLoading}
+                  runId={entry?.run_id}
+                  feedback={entry?.feedback}
                 />
               );
             });