Update 'px' to 'PX'

[andy1li]

Note

Switches SET expiration flag to PX in fixtures and refreshes golden outputs (paths, ports, IDs, hexdumps, ordering).

• Expiry/commands:
  • Use uppercase PX for SET expiration in fixtures (was px).
• Fixtures/logs:
  • Update paths from /tmp/... to /private/tmp/... in RDB-related fixtures.
  • Refresh recorded outputs: connection ports, replication IDs, RDB hexdumps, stream IDs/timestamps, and some key ordering.
  • No functional code changes; only test fixture/golden output updates to match current behavior.

^{Written by Cursor Bugbot for commit b37ce70. This will update automatically on new commits. Configure here.}

[github-actions]

Triggered a Github Actions job to update fixtures.