feat: wrapped invoices scenario

[rolznz]

Currently Alby Hub doesn't properly support this scenario

TODOs:

• fix Alby Hub self-payments fix: intercept self hold payments based on invoice rather than payment hash hub#2027
• update NWC faucet to use that hub branch
• Add note that this is a preview and not fully supported yet. Contact us if you are interested in this usecase.
• Add note about this min_final_cltv_expiry_delta requirement to ensure the service cannot be cheated

FOLLOW-UPs - move to different issues:

• add knowledge of wrapped invoices to alby agent skill (slightly different usage than normal HOLD invoices) - Add knowledge of wrapped invoices alby-agent-skill#17
• Update the example to ensure that this min_final_cltv_expiry_delta is set - Wrapped invoices - ensure min_final_cltv_expiry_delta is set #7