Upload pasted images and dropped files to the host for remote sessions

[wildsurfer]

I run Claude Code on a remote Mac mini and use it from my laptop through agtermctl zmx attach. I cannot give it a screenshot or a file from my laptop:

• Claude Code's Ctrl+V reads the clipboard of the machine where it runs, so it sees the mini's clipboard, not my laptop's;
• ⌘V with an image does nothing;
• a dropped file inserts my local path, which does not exist on the mini.

My workaround now is an Apple Shortcut. It uploads the screenshot to the mini and copies the remote path, and then I paste it. It works only for screenshots. For other files I do the same thing by hand.

In #429 the answer was that the image belongs to the program in the pane. For a remote session this is not possible: the program runs on the other Mac and cannot see my clipboard or my files. Only agterm knows both machines and already has the ssh connection to the host. Also, this is only for remote sessions and only for my own paste or drop in the app, never for a clipboard read by a program on the other side.

What I would like:

1. In a remote session, pasting an image or files, or dropping a file on the pane, uploads it to the host and pastes the remote path instead of the local one.
2. The upload shows progress and a clear error if it fails.
3. The same upload is available from agtermctl, so scripts and keymap commands can use it.
4. It can be turned off, and local sessions are not changed at all.

A script with scp and agtermctl session paste can do part of this today, but not drag and drop.

Would you accept something like this?

[umputun]

not as an upload feature, but the screenshot case works today without app changes: remote-image-paste in the cookbook. One chord copies the image from this Mac's clipboard to the mini's clipboard over ssh, and after the success panel appears, a normal ctrl+v pastes it into Claude Code or codex there as a real image. Both Claude Code and codex read the transferred image correctly in tests on another Mac.

files are the other half. A dropped file still inserts its local path and there is no hook to pass it to a script, so for files it's scp plus agtermctl session type with the remote path for now.