Layout jump when navigating up from SFTP folder

Steps to reproduce

1. Open Nemo to an SFTP folder (e.g. sftp://192.168.0.105:2222/storage/emulated/0/Bluetooth)
2. Wait for the folder contents to fully load
3. Navigate up one level (Alt+Up)

Expected behavior

Parent folder contents appear in their final positions immediately — no layout shift.

Actual behavior

When navigating up, the layout jumps:

1. First, only the previously-visited subfolder (Bluetooth) appears in the file list
2. Then all other folders/files load in
3. The Bluetooth folder jumps to its correct alphabetical position

This creates a visible layout shift — the Bluetooth folder "jumps" from one position to another.

Screen recording

Slow-motion video (4× slowed, frames 6–10s) showing the jump:

https://gofile.io/d/8rY76g

Environment

• Nemo version: 6.6.3
• Distro: Linux Mint 22.3 (zena)
• Desktop: Cinnamon
• Connection: SFTP over SSH

Notes

The jump does not happen consistently — it depends on timing of the SFTP directory listing response. When the listing arrives in one batch, no jump occurs. When it arrives in two stages (cached subfolder first, then full listing), the jump is visible.

This seems specific to the SFTP backend's asynchronous directory loading.

Start by reproducing the issue in Nemo with an SFTP folder and observing the directory listing as it arrives in stages. Trace the SFTP backend's asynchronous directory loading and the file-list layout updates; done means navigating up no longer causes a cached folder to jump when the full listing arrives.