feat(fwdctl/launch): add SSM-based monitor/follow flow for cloud-init and bootstrap progress (2/4)

[AminR443]

Why this should be merged

This PR introduces launch monitoring for fwdctl using AWS SSM. It closes the visibility gap after instance startup by exposing cloud-init stage progress and optional bootstrap re-execution progress without requiring SSH access.

This is important for:

• Faster debugging when launch stages fail
• Better operator visibility during long-running setup/replay flows
• More deterministic failure context (stage, command index, exit code)

How this works

The launcher now writes structured cloud-init state to /var/log/cloud-init-state.json and updates it after each stage/command via a small helper script. A new SSM monitor module polls this state and renders progress in real time.

How this was tested

Manually.

Design Notes

1. SSM-first monitoring: SSM is chosen over SSH so monitoring works with standard AWS controls and without opening additional access paths.
2. Structured state file: stage state is persisted as JSON in cloud-init, making progress/failure reporting deterministic instead of log-pattern-based.