fork-infra: drop cockpit, .sops.yaml, e2e workflow from PR 68

These were re-added on this branch while fixing the origin/main pickup
regression (cb81ecd + the d94624a cockpit rename), but they are fork
infra deleted from main by 53d09cc, not part of the adaptive_export
auth work. Carried on restore-fork-infra-main for a separate PR into
main. skaffold/skaffold_cloud.yaml is left in place — it is an upstream
file, not a clean fork-only add.

Author: pixie-agent