[TEST - RLN]: Improve penalty TX coverage and define vanilla LN node compatibility testing

[ABallarini]

This issue focuses on expanding test coverage in two main areas:

1. Penalty Transactions: Testing breach-remedy and revocation mechanics (incorporating insights from Zoe’s Viareggio presentation/interview on @RGB_hub).
2. Vanilla Channel Compatibility: Establishing an integration test blueprint to define and test what "compatibility with other LN nodes for vanilla channels" means across standard Bitcoin Lightning node implementations (ldk-node, ldk-node-server, LND, Eclair, and LNC).