fix: clean up E2E temp directories on all platforms

[paolino]

Summary

When E2E tests get cancelled (timeout or cancel-in-progress), withSystemTempDirectory cleanup never runs, leaking ~17GB per run. This filled the Linux runner's /tmp tmpfs and broke all CI jobs (see #5195 for the Linux fix).

The same issue affects the Windows E2E workflow (windows-e2e.yml), which also lacks a cleanup step.

Fix

Add an if: always() cleanup step to windows-e2e.yml:

      - name: Cleanup temp directories
        if: always()
        shell: pwsh
        run: |
          Get-ChildItem $env:TEMP -Directory -Filter "e2e*" | Remove-Item -Recurse -Force

Status

• No PR yet — quick fix (~10 lines)
• Linux already fixed in fix: clean up E2E temp directories on cancellation #5195
• Windows still leaking