PRD 0007: thread the DockerSSHGate through the bottle lifecycle.
- DockerBottlePlan gains gate_plan: SSHGatePlan.
- prepare.resolve_plan accepts a gate and renders its entrypoint
script next to the pipelock yaml.
- launch.launch starts the gate sidecar after pipelock (so it's on
the same internal + egress networks) and registers its stop in
the ExitStack. Skipped when the bottle has no ssh entries.
- DockerBottleBackend instantiates DockerSSHGate alongside the
pipelock proxy.
- bottle_plan.print + to_dict surface the upstream table so
--dry-run shows the per-host listen-port mapping.
ssh_config provisioning still points at pipelock; that swap lands
in the next commit so this one stays a pure wiring change.
didericis
2533f8a00b