Merge upstream/experimental into feat/citations

Resolved conflicts:
- backend/src/gateway/routers/artifacts.py: Keep citations block removal for markdown downloads
- frontend/src/components/workspace/messages/message-list-item.tsx: Keep improved citation handling with rehypePlugins, humanMessagePlugins, and CitationsLoadingIndicator

Co-authored-by: Cursor <cursoragent@cursor.com>

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

@@ -220,11 +220,13 @@ function ToolCall({
         {Array.isArray(result) && (
           <ChainOfThoughtSearchResults>
             {result.map((item) => (
-              <ChainOfThoughtSearchResult key={item.url}>
-                <a href={item.url} target="_blank" rel="noreferrer">
-                  {item.title}
-                </a>
-              </ChainOfThoughtSearchResult>
+              <Tooltip key={item.url} content={item.snippet}>
+                <ChainOfThoughtSearchResult key={item.url}>
+                  <a href={item.url} target="_blank" rel="noreferrer">
+                    {item.title}
+                  </a>
+                </ChainOfThoughtSearchResult>
+              </Tooltip>
             ))}
           </ChainOfThoughtSearchResults>
         )}

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

@@ -285,7 +285,7 @@ function UploadedFilesList({ files, threadId }: { files: UploadedFile[]; threadI
   if (files.length === 0) return null;
 
   return (
-    <div className="mb-2 flex flex-wrap gap-2">
+    <div className="mb-2 flex flex-wrap justify-end gap-2">
       {files.map((file, index) => (
         <UploadedFileCard key={`${file.path}-${index}`} file={file} threadId={threadId} />
       ))}