test(e2e): reuse config.TrunkConfig in the harness Config to stop silently dropping new manifest fields

[joshua-temple]

The multistep e2e harness Config (e2e/harness/scenario.go) mirrors config.TrunkConfig field-by-field. Twice during the fleet-orchestration work a new manifest field (release_trigger, cli_version/cli_version_sha) was silently dropped on marshal because the harness struct lacked it, failing the scenario only at Docker-e2e time. Reuse config.TrunkConfig directly (or embed it) so new fields flow through automatically. Same #350-class hazard, in the test harness.