v11.15.0

• LoanBrokerCover (Xrpl.Sugar) computes a loan broker's first-loss cover offline from the LoanBroker and Vault entries, as rippled's LoanBrokerCoverDeposit, LoanBrokerCoverWithdraw, LoanBrokerCoverClawback and minimumBrokerCover do (#290). MinimumCover is the minimum LoanBrokerCoverWithdraw keeps: CoverRateMinimum of DebtTotal rounded up, to the scale of the vault's AssetsTotal under fixCleanup3_2_0 and to the scale of DebtTotal before it. MaxWithdrawable is the largest withdrawal the node accepts. CheckDeposit rounds the deposit down to the scale of CoverAvailable under fixCleanup3_2_0; CheckWithdraw and CheckClawback check the amount against the minimum, which a pre-fix clawback does not round to the asset; MaxClawback is what a clawback without an amount takes. The checks return LoanBrokerCoverQuote (Amount, CoverBefore, CoverAfter, MinimumCover, Refusal, RefusalReason) with temBAD_AMOUNT, tecPRECISION_LOSS, tecINSUFFICIENT_FUNDS or tecNO_PERMISSION
• PreviewSugar.PreviewLoanBrokerCoverDeposit, PreviewLoanBrokerCoverWithdraw and PreviewLoanBrokerCoverClawback return LoanBrokerCoverOutcome (CoverBefore, CoverAfter, MinimumCover, MaxWithdrawable, BrokerAfter). The preview reads the broker's vault with ledger_entry, and the rules with LedgerRules.FromNodeAsync unless they are passed. LoanBrokerCoverOutcome.FromMetadata reads the same from a validated transaction
• AssetRounding.ScaleInMode (internal) takes scale() in the context's rounding mode, as minimumBrokerCover does inside its upward guard
• Docs: withdrawing cover in LendingProtocol-Guide (both languages)
• Tests: TestULoanBrokerCover covers XRP, IOU and MPT vaults on both sides of fixCleanup3_2_0, an IOU vault whose AssetsTotal scale differs from the DebtTotal scale, and a 17-digit AssetsTotal that the upward guard takes to the next exponent; TestILoanBrokerCover withdraws MaxWithdrawable from IOU, XRP and MPT brokers, gets tecINSUFFICIENT_FUNDS from the node for one unit more and for the pre-fix maximum as CheckWithdraw does, claws back what CheckClawback says, and compares each preview with the submitted transaction