Desktop app (Windows 1.52386.6): SendUserFile card opens a preview drawer with no save/download control, even with display: attach

## Summary

In the Claude desktop app on Windows (Code tab), a file card sent from a session with `SendUserFile` no longer offers a download. Clicking the card opens a preview drawer, and the drawer has no save control either, so there is no way to save the file to a folder of my choosing. Until recently, clicking the card's icon opened a normal Windows save dialog.

The files are plugin `.zip` archives, which the drawer cannot preview anyway, so the card is a dead end for the exact file type it is meant to deliver.

## Environment

- Claude desktop app for Windows: 1.52386.6 (from `AppData\Local\Claude\Logs\main.log`)
- Claude Code (bundled): 2.1.274 (recorded in the session transcript)
- Windows 11 Home 10.0.26200
- Files: two `.zip` archives, 15 KB and 268 KB

## Steps to reproduce

1. In a Code tab session, have Claude send a `.zip` with `SendUserFile` (`display: "attach"`, and also with `display` unset; both tried).
2. Click the file card in the conversation.

## Expected

A download / save-as dialog, as before, so the user chooses where the file lands.

## Actual

A preview drawer opens beside the conversation. It shows nothing useful for a zip and has no download or save-to button. Right-click offers nothing. The same happens for `display: "attach"`, which the tools reference documents as "a download card only".

## Notes

- Same defect as #86337 (Windows: cards open the file instead of offering a download). Reporting separately with the current version numbers, and to record that `display: "attach"` and the drawer both lack a save control.
- Workarounds tried from the session side, none of which work: publishing the zip through the Artifact tool (refuses `.zip`), opening a local download page in the built-in browser pane (`file://` is blocked, `about:blank#blocked`).
- The only remaining route is to have the session write the file to a folder on disk, which defeats the point of a download card and is not something I want a session doing on its own.

Please restore the save dialog on the card (or add a Save button to the drawer), and document how a user is meant to save a delivered file.

No repository file or test is identified. Reproduce on Windows with Claude desktop 1.52386.6 by sending a .zip through SendUserFile using display: "attach", then compare the card and preview drawer behavior with the expected save dialog or a Save control; review related issue #86337 for context.

Written by the indexing model from the issue text.