merge: upstream/experimental with citations feature

- Merge upstream changes including image search, tooltips, and UI improvements
- Keep citations feature with inline hover cards
- Resolve conflict in message-list-item.tsx: use upstream img max-width (90%) while preserving citations logic
- Maintain file upload improvements with citations support

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

frontend/src/core/i18n/locales/en-US.ts

@@ -106,6 +106,9 @@ export const enUS: Translations = {
     needYourHelp: "Need your help",
     useTool: (toolName: string) => `Use "${toolName}" tool`,
     searchForRelatedInfo: "Search for related information",
+    searchForRelatedImages: "Search for related images",
+    searchForRelatedImagesFor: (query: string) =>
+      `Search for related images for "${query}"`,
     searchOnWebFor: (query: string) => `Search on the web for "${query}"`,
     viewWebPage: "View web page",
     listFolder: "List folder",