Make Lending setup compatible with LendingProtocolV1_1

[manasip-prog]

Summary

Fixes Lending setup and role signatures for LendingProtocolV1_1 and fixCleanup3_4_0, required for the 3.4.0 Antithesis run.

The amendment requires closed-ended Vaults for new Loan Brokers. Additionally, fixCleanup3_4_0 binds counterparty and sponsor signatures to dedicated prefixes; xrpl-py 5.1.0 still signs both with the legacy transaction prefix, causing Counterparty: Invalid signature.

Changes

• Create dedicated XRP lending Vaults as closed-ended.
• Keep them in Subscription long enough for setup deposits, then wait for Investment before creating loans.
• Restrict valid Loan Broker and Loan paths to eligible Vaults and schedules.
• Sign CounterpartySignature with CPT\0 and SponsorSignature with SPN\0.
• Share the role-signing implementation across setup, lending, sponsorship, and modifiers.
• Ignore generated root testnet/ output.

Validation

• Deterministic cryptographic verification for both 3.4 role prefixes
• check-imports
• check-endpoints
• check-fuzz-coverage
• check-modifier-coverage
• Ruff lint and format
• mypy
• basedpyright

[lmaisons]

Nothing stands out as problematic. Fixes a blocking problem. Approving.