Amendment XLS: Early-exit fee

[a1q123456]

Partner validation: brokers already operate early-withdrawal penalties and want the option to let a depositor exit before RedemptionDate. The closed-ended Vault as specified admits no exceptions at any price, and an operator willing to offer one on terms that do not penalise the depositors who stay has no way to express it.

Scoped as a strictly additive, opt-in patch rather than a change to the lifecycle. An owner who sets no rate gets today's behaviour exactly; the entry side is untouched, with VaultDeposit still blocked for the whole Investment phase, and SubscriptionDate / RedemptionDate semantics unchanged. The exit remains best-efforts against Vault.AssetsAvailable — not a redemption right, and unhonourable at any rate by a Vault with its capital fully deployed (Security Considerations).