Bug Description

Using openclaw backup create command, if the process is killed due to timeout, large .tmp temporary files are left behind in the current directory without cleanup.

Steps to Reproduce

1. Set a short timeout (e.g., 300 seconds)
2. Run openclaw backup create
3. Wait for timeout

Actual Impact

• 7 consecutive timeouts accumulated 6 .tmp files totaling 12.6GB
• Disk usage spiked from 56% to 89%

Expected Behavior

1. Clean up .tmp files immediately after backup completes
2. Use atomic rename to ensure file only appears on success
3. Clean up temporary files even on timeout/exception

Environment

• OpenClaw 2026.3.8
• Linux