fix: saving a file (screenshot, response) in remote worker will not forward to client

[ocervell]

When running in worker mode with a remote worker, there are a few problems when taking a screenshot with httpx:

• Screenshot path on client shows remote path (path disclosure / leak)
• Screenshot / file path is not accessible on client since it's a remote path

We could have the problem for any task saving files in the remote machine. We might need a broader implementation like:

General implem:

• Task saves remote path
• Task loads remote path as base64-encoded bytes
• [client] Client loads remote path locally and saves it to runner output folder.